Scholarly Publications - BAM

Permanent URI for this collectionhttps://hdl.handle.net/11693/115580

Browse

Now showing 1 - 20 of 303

Open Access
Functional characterization of Des-IGF-1 action at excitatory synapses in the CA1 region of rat hippocampus
(American Physiological Society, 2005) Ramsey, M. M.; Adams, Michelle M.; Ariwodola, O. J.; Sonntag, W. E.; Weiner, J.
Insulin-like growth factor-1 (IGF-1) and growth hormone play a major role in the growth and development of tissues throughout the mammalian body. Plasma IGF-1 concentrations peak during puberty and decline with age. We have determined that chronic treatments to restore plasma IGF-1 concentrations to adult levels attenuate spatial learning deficits in aged rats, but little is known of the acute actions of IGF-1 in the brain. To this end, we utilized hippocampal slices from young Sprague-Dawley rats to characterize the acute effects of des-IGF-1 on excitatory synaptic transmission in the CA1 region. We observed a 40% increase in field excitatory postsynaptic potential (fEPSP) slope with application of des-IGF-1 (40 ng/ml) and used whole cell patch-clamp recordings to determine that this enhancement was due to a postsynaptic mechanism involving α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate (AMPA) but not N-methyl-d-aspartate receptors. Furthermore, the enhancement was completely blocked by the broad-spectrum tyrosine kinase inhibitor, genistein (220 μM), and significantly reduced by the PI3K blockers wortmannin (1 μM) and 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (10 μM), suggesting that the effect was predominantly dependent on PI3K activation. This characterization of the acute actions of des-IGF-1 at hippocampal excitatory synapses may provide insight into the mechanism by which long-term increases in plasma IGF-1 impart cognitive benefits in aged rats. Increases in AMPA receptor-mediated synaptic transmission may contribute directly to cognitive improvement or initiate long-term changes in synthesis of proteins such as brain-derived neurotrophic factor that are important to learning and memory.
Open Access
Spatial learning and memory deficits after whole-brain irradiation are associated with changes in nmda receptor subunits in the hippocampus
(Radiation Research Society., 2006) Shi, L.; Adams, Michelle M.; Long, A.; Carter, C.; Bennett, C.; Sonntag, W.; Nicolle, M.; Robbins, M.; D'Agostino, R.; Brunso-Bechtold, J.
Whole-brain irradiation is used for the treatment of brain tumors, but can it also induce neural changes, with progressive dementia occurring in 20–50% of long-term survivors. The present study investigated whether 45 Gy of whole-brain irradiation delivered to 12-month-old Fischer 344 × Brown Norway rats as nine fractions over 4.5 weeks leads to impaired Morris water maze (MWM) performance 12 months later. Compared to sham-irradiated rats, the irradiated rats demonstrated impaired MWM performance. The relative levels of the NR1 and NR2A but not the NR2B subunits of the NMDA receptor were significantly higher in hippocampal CA1 of irradiated rats compared to control rats. No significant differences were detected for these NMDA subunits in CA3 or dentate gyrus. Further analysis of CA1 revealed that the relative levels of the GluR1 and GluR2 subunits of the AMPA receptor and synaptophysin were not altered by whole-brain irradiation. In summary, a clinically relevant regimen of fractionated whole-brain irradiation led to significant impairments in spatial learning and reference memory and alterations in the relative levels of subunits of the NMDA, but not the AMPA, receptors in hippocampal CA1. These findings suggest for the first time that radiation-induced cognitive impairments may be associated with alterations in glutamate receptor composition.
Open Access
Meta- and paracontrast reveal differences between contour- and brightness-processing mechanisms
(Elsevier, 2006) Breitmeyer, B. G.; Kafalıgönül, Hulusi; Öğmen, H.; Mardon, L.; Todd, S.; Ziegler, R.
We investigated meta- and paracontrast masking using tasks requiring observers to judge the surface brightness or else the contours of target stimuli. The contour task revealed strongest metacontrast at SOAs shorter than those obtained for the brightness task. Paracontrast revealed related temporal differences between the tasks. Additionally, the paracontrast results support the existence not only of prolonged inhibitory effects but also of facilitatory effects. The combined results comport with the existence of cortical mechanisms for: (i) fast contour processing, (ii) slow surface-brightness processing, (iii) prolonged inhibition, and (iv) facilitation.
Open Access
Caloric restriction eliminates the aging-related decline in NMDA and AMPA receptor subunits in the rat hippocampus and induces homeostasis
(Elsevier, 2007) Shi, L.; Adams, Michelle M.; Linville, M.; Newton, I.; Forbes, M.; Long, A.; Riddle, D.; Brunso-Bechtold, J.
Caloric restriction (CR) extends life span and ameliorates the aging-related decline in hippocampal-dependent cognitive function. In the present study, we compared subunit levels of NMDA and AMPA types of the glutamate receptor and quantified total synapses and multiple spine bouton (MSB) synapses in hippocampal CA1 from young (10 months), middle-aged (18 months), and old (29 months) Fischer 344×Brown Norway rats that were ad libitum (AL) fed or caloric restricted (CR) from 4 months of age. Each of these parameters has been reported to be a potential contributor to hippocampal function. Western blot analysis revealed that NMDA and AMPA receptor subunits in AL animals decrease between young and middle age to levels that are present at old age. Interestingly, young CR animals have significantly lower levels of glutamate receptor subunits than young AL animals and those lower levels are maintained across life span. In contrast, stereological quantification indicated that total synapses and MSB synapses are stable across life span in both AL and CR rats. These results indicate significant aging-related losses of hippocampal glutamate receptor subunits in AL rats that are consistent with altered synaptic function. CR eliminates that aging-related decline by inducing stable NMDA and AMPA receptor subunit levels.
Open Access
Estrogen and aging affect synaptic distribution of phosphorylated LIM kinase (pLIMK) in CA1 region of female rat hippocampus
(Elsevier, 2008) Yildirim, M.; Janssen, W. G. M.; Tabori, N. E.; Adams, Michelle M.; Yuen, G. S.; Akama, K. T.; McEwen, B. S.; Milner, T. A.; Morrison, J. H.
17β-Estradiol (E) increases axospinous synapse density in the hippocampal CA1 region of young female rats, but not in aged rats. This may be linked to age-related alterations in signaling pathways activated by synaptic estrogen receptor α (ER-α) that potentially regulate spine formation, such as LIM-kinase (LIMK), an actin depolymerizing factor/cofilin kinase. We hypothesized that, as with ER-α, phospho-LIM-kinase (pLIMK) may be less abundant or responsive to E in CA1 synapses of aged female rats. To address this, cellular and subcellular distribution of pLIMK-immunoreactivity (IR) in CA1 was analyzed by light and electron microscopy in young and aged female rats that were ovariectomized and treated with either vehicle or E. pLIMK-IR was found primarily in perikarya within the pyramidal cell layer and dendritic shafts and spines in stratum radiatum (SR). While pLIMK-IR was occasionally present in terminals, post-embedding quantitative analysis of SR showed that pLIMK had a predominant post-synaptic localization and was preferentially localized within the postsynaptic density (PSD). The percentage of pLIMK-labeled synapses increased (30%) with E treatment (P<0.02) in young animals, and decreased (43%) with age (P<0.002) regardless of treatment. The pattern of distribution of pLIMK-IR within dendritic spines and synapses was unaffected by age or E treatment, with the exception of an E-induced increase in the non-synaptic core of spines in young females. These data suggest that age-related synaptic alterations similar to those seen with ER-α occur with signaling molecules such as pLIMK, and support the hypothesis that age-related failure of E treatment to increase synapse number in CA1 may be due to changes in the molecular profile of axospinous synapses with respect to signaling pathways linked to formation of additional spines and synapses in response to E.
Open Access
Distinct perceptual grouping pathways revealed by temporal carriers and envelopes
(Association for Research in Vision and Ophthalmology, 2008) Rainville, S.; Clarke, Aaron
S. E. Guttman, L. A. Gilroy, and R. Blake (2005) investigated whether observers could perform temporal grouping in multi-element displays where each local element was stochastically modulated over time along one of several potential dimensions—or “messenger types”—such as contrast, position, orientation, or spatial scale. Guttman et al.'s data revealed that grouping discards messenger type and therefore support a single-pathway model that groups elements with similar temporal waveforms. In the current study, we carried out three experiments in which temporal-grouping information resided either in the carrier, the envelope, or the combined carrier and envelope of each messenger's timecourse. Results revealed that grouping is highly specific for messenger type if carrier envelopes lack grouping information but largely messenger nonspecific if carrier envelopes contain grouping information. These imply that temporal grouping is mediated by several messenger-specific carrier pathways as well as by a messenger-nonspecific envelope pathways. Findings also challenge simple temporal-filtering accounts of perceptual grouping (E. H. Adelson & H. Farid, 1999).
Open Access
Metacontrast masking and stimulus contrast polarity
(Elsevier, 2008) Breitmeyer, B.; Tapia, E.; Kafalıgönül, Hulusi; Öğmen, H.
A recent report [Becker, M. W., & Anstis S. (2004). Metacontrast masking is specific to luminance polarity. Vision Research, 44, 2537–2543] of a failure to obtain metacontrast with target and mask stimuli of opposite contrast polarity is reexamined in an experiment that systematically varies not only stimulus contrast polarity but also target size and target-mask onset asynchrony (SOA). The results show that (a) although, as previously shown [Breitmeyer, B. G. (1978a). Metacontrast with black and white stimuli: Evidence of inhibition of on and off sustained activity by either on or off transient activity. Vision Research, 18, 1443–1448], metacontrast is weaker with stimuli of opposite contrast polarity, (b) substantial metacontrast can be obtained with targets and masks of opposite contrast polarity, especially (c) when the target is small. We conclude that Becker and Anstis’s failure to obtain metacontrast with stimuli of opposite contrast polarity is due to their use of a single, relatively large, SOA value.
Open Access
Full‐brain coverage and high‐resolution imaging capabilities of passband b‐SSFP fMRI at 3T
(Wiley‐Liss, Inc., 2008) Lee, J. H.; Dumoulin, S.; Sarıtaş, Emine Ülkü; Glover, G.; Wandell, B.; Nishimura, D.; Pauly, J.
Passband balanced-steady-state free precession (b-SSFP)fMRI is a recently developed method that utilizes the passband(ﬂat portion) of the b-SSFP off-resonance response to measureMR signal changes elicited by changes in tissue oxygenationfollowing increases in neuronal activity. Rapid refocusing andshort readout durations of b-SSFP, combined with the relativelylarge ﬂat portion of the b-SSFP off-resonance spectrum allowsdistortion-free full-brain coverage with only two acquisitions.This allows for high-resolution functional imaging, without thespatial distortion frequently encountered in conventional high-resolution functional images. Finally, the 3D imaging compati-bility of the b-SSFP acquisitions permits isotropic-voxel-sizehigh-resolution acquisitions. In this study we address some ofthe major technical issues involved in obtaining passband b-SSFP-based functional brain images with practical imaging pa-rameters and demonstrate the advantages through breath-holding and visual ﬁeld mapping experiments. Magn ResonMed 59:1099 –1110, 2008.
Open Access
Attention-dependent representation of a size illusion in human V1
(Cell Press, 2008) Fang, F.; Boyacı, Hüseyin; Kersten, D.; Murray, S.O.
One of the most fundamental properties of human primary visual cortex (V1) is its retinotopic organization, which makes it an ideal candidate for encoding spatial properties, such as size, of objects. However, three-dimensional (3D) contextual information can lead to size illusions that are reflected in the spatial pattern of activity in V1 [1]. A critical question is how complex 3D contextual information can influence spatial activity patterns in V1. Here, we assessed whether changes in the spatial distribution of activity in V1 depend on the focus of attention, which would be suggestive of feedback of 3D contextual information from higher visual areas. We presented two 3D rings at close and far apparent depths in a 3D scene. When subjects fixated its center, the far ring appeared to be larger and occupy a more eccentric portion of the visual field, relative to the close ring. Using functional magnetic resonance imaging, we found that the spatial distribution of V1 activity induced by the far ring was also shifted toward a more eccentric representation of the visual field, whereas that induced by the close ring was shifted toward the foveal representation, consistent with their perceptual appearances. This effect was significantly reduced when the focus of spatial attention was narrowed with a demanding central fixation task. We reason that focusing attention on the fixation task resulted in reduced activity in-and therefore reduced feedback from-higher visual areas that process the 3D depth cues.
Open Access
Stability of local brain levels of insulin-like growth factor-I in two well-characterized models of decreased plasma IGF-I
(Taylor & Francis, 2009) Adams, Michelle M.; Forbes, M; Linville, M.; Riddle, D.; Sonntag, W.; Brunso-Bechtold, J.
Insulin-like growth factor-I (IGF-I), a functionally important neurotrophic factor, impacts tissues throughout the body including the central nervous system. In addition to the significant proportion of IGF-I that is synthesized in the liver and released into the plasma, IGF-I is expressed locally in tissues. The present study investigated the relationship between plasma and local brain levels of IGF-I in two well-characterized models of decreased IGF-I. The first is an adult-onset growth hormone deficiency (AOGHD) model, and the second is a caloric restriction (CR) model. In the first cohort of animals from both models, the hippocampus was removed from the brain immediately following decapitation, and in the second cohort, the animals were perfused transcardially with phosphate buffered saline to remove cerebral blood prior to harvesting the hippocampus. Our results demonstrated that although the plasma IGF-I levels were decreased in the CR and AOGHD rats compared to controls, the hippocampal IGF-I levels did not differ among the groups. These data suggest that local brain IGF-I levels are regulated in a different manner than plasma IGF-I levels.
Open Access
Effects of contrast polarity in paracontrast masking
(Springer New York, 2009) Kafalıgönül, Hulusi; Breitmeyer, B.; Öğmen, H.
The visibility of a target stimulus can be suppressed (inhibition) or increased (facilitation) during paracontrast masking. Three processes have been proposed to be involved in paracontrast masking: brief inhibition, facilitation, and prolonged inhibition (Breitmeyer et al., 2006). Brief inhibition is observed when the mask precedes the target at short stimulus onset asynchronies (SOAs) ranging from -10 to -30 msec, whereas prolonged inhibition is effective up to very large SOAs of -450 msec. Facilitation, enhancement in target visibility, can be observed at SOA values between -20 and -110 msec. We further investigated these processes by changing target-mask spatial separation and the contrast polarity of the mask. Our results show that (1) facilitation weakens when spatial separation between the target and mask is increased or when they have opposite contrast polarity, and (2) brief inhibition turns into facilitation for the opposite-polarity mask, whereas prolonged inhibition does not change significantly. These results suggest a fast inhibition mechanism realized in the contrast-specific center-surround antagonism of classical receptive fields for brief inhibition and a slower, higher level cortical processing that is indifferent to contrast polarity for prolonged inhibition.
Open Access
Border ownership selectivity in human early visual cortex and its modulation by attention
(Society for Neuroscience, 2009) Fang, F.; Boyacı, Hüseyin; Kersten, D.
Natural images are usually cluttered because objects occlude one another. A critical aspect of recognizing these visual objects is to identify the borders between image regions that belong to different objects. However, the neural coding of border ownership in human visual cortex is largely unknown. In this study, we designed two simple but compelling stimuli in which a slight change of contextual information could induce a dramatic change of border ownership. Using functional MRI adaptation, we found that border ownership selectivity in V2 was robust and reliable across subjects, and it was largely dependent on attention. Our study provides the first human evidence that V2 is a critical area for the processing of border ownership and that this processing depends on the modulation from higher-level cortical areas.
Open Access
Estimating the glossiness transfer function induced by illumination change and testing its transitivity
(Association for Research in Vision and Ophthalmology, 2010) Doerschner, K.; Boyacı, Hüseyin; Maloney, Laurence T.
The light reflected from a glossy surface depends on the reflectance properties of that surface as well as the flow of light in the scene, the light field. We asked four observers to compare the glossiness of pairs of surfaces under two different realword light fields, and used this data to estimate a transfer function that captures how perceived glossiness is remapped in changing from one real-world light field to a second. We wished to determine the form of the transfer function and to test whether for any set of three light fields the transfer function from light field 1 to light field 2 and the transfer function from light field 2 to light field 3 could be used to predict the glossiness transfer function from light field 1 to light field 3. Observers' estimated glossiness transfer functions for three sets of light fields were best described by a linear model. The estimated transfer functions exhibited the expected transitivity pattern for three out of four observers. The failure of transitivity for one observer, while significant, was less than 12.5% of the gloss range.
Open Access
Auditory modulation of visual apparent motion with short spatial and temporal intervals
(Association for Research in Vision and Ophthalmology, 2010) Kafalıgönül, Hulusi; Stoner, G.
Recently, E. Freeman and J. Driver (2008) reported a cross-modal temporal interaction in which brief sounds drive the perceived direction of visual apparent-motion, an effect they attributed to “temporal capture” of the visual stimuli by the sounds (S. Morein-Zamir, S. Soto-Faraco, & A. Kingstone, 2003). Freeman and Driver used “long-range” visual motion stimuli, which travel over long spatial and temporal intervals and engage high-order cortical areas (K. G. Claeys, D. T. Lindsey, E. De Schutter, & G. A. Orban, 2003; Y. Zhuo et al., 2003). We asked whether Freeman and Driver’s temporal effects extended to the short-range apparent-motion stimuli that engage cortical area MT, a lower-order area with well-established spatiotemporal selectivity for visual motion (e.g. A. Mikami, 1991, 1992; A. Mikami, W. T. Newsome, & R. H. Wurtz, 1986a, 1986b; W. T. Newsome, A. Mikami, & R. H. Wurtz, 1986). Consistent with a temporal-capture account, we found that static sounds bias the perception of both the direction (Experiment 1) and the speed (Experiment 2) of short-range motion. Our results suggest that auditory timing may interact with visual spatiotemporal processing as early as cortical area MT. Examination of the neuronal responses of this well-studied area to the stimuli used in this study would provide a test and might provide insight into the neuronal representation of time.
Open Access
Perceived glossiness in high dynamic range scenes
(Association for Research in Vision and Ophthalmology, 2010) Doerschner, K.; Maloney,Laurence T.; Boyaci, Hüseyin
We investigated how spatial pattern, background, and dynamic range affect perceived gloss in brightly lit real scenes. Observers viewed spherical objects against uniform backgrounds. There were three possible objects. Two were black matte spheres with circular matte white dots painted on them (matte-dot spheres). The third sphere was painted glossy black (glossy black sphere). Backgrounds were either black or white matte, and observers saw each of the objects in turn on each background. Scenes were illuminated by an intense collimated source. On each trial, observers matched the apparent albedo of the sphere to an albedo reference scale and its apparent gloss to a gloss reference scale. We found that mattedot spheres and the black glossy sphere were perceived as glossy on both backgrounds. All spheres were judged to be significantly glossier when in front of the black background. In contrast with previous research using conventional computer displays, we find that background markedly affects perceived gloss. This finding is surprising because darker surfaces are normally perceived as glossier (F. Pellacini, J. A. Ferwerda, & D. P. Greenberg, 2000). We conjecture that there are cues to surface material signaling glossiness present in high dynamic range scenes that are absent or weak in scenes presented using conventional computer displays.
Open Access
Perceptual grouping-dependent lightness processing in human early visual cortex
(Association for Research in Vision and Ophthalmology, 2010) Boyaci, H.; Fang, F.; Murray, S. O.; Kersten, D.
Lightness, the perceived relative achromatic reectance of a surface, depends strongly on the context within which the surface is viewed. Modest changes in the two-dimensional conguration or three-dimensional scene geometry may lead to profound variations in lightness even though the surface luminance remains constant. Despite recent progress, we are far from a complete understanding of how various aspects of spatial context affect lightness processing in the cortex. Here we use a novel stimulus to show that perceptual grouping through occluders can affect lightness. We first report behavioral results showing how lightness across occlusion depends on spatially distant image features, including luminance and contrast. Next using functional magnetic resonance imaging (fMRI) we show that human early visual cortex responds strongly to occlusion-dependent lightness variations with little or no attention. These results suggest that elements of three-dimensional scene interpretation play a role in early cortical processing of lightness.
Open Access
Perceptual asynchronies and the dual-channel differential latency hypothesis
(Cambridge University Press, 2010) Kafalıgönül, Hulusi; Patel, S.; Öğmen, H.; Bedell, H.; Purushothaman, G.; Nijhawan, R.; Khurana, B.
The dual-channel differential latency hypothesis (Öğmen et al. 2004) successfully accounts for many aspects of the flash-lag effect (FLE). Here we use the dual-channel differential latency hypothesis to explain an illusion of perceived line length that can be viewed as one component of an illusion reported by Cai and Schlag (2001a). In the phenomenon studied here, a flash is presented collinear with a moving line that is simultaneously changing in length. The moving line is perceived to be misaligned with the flash (the FLE) and the length of the moving line is perceived to differ from its physical length at the instant of the flash. We designate this phenomenon the Cai line-Length Effect (CLE). Our analysis treats a horizontally moving line that also changes its vertical length as composed of two simultaneous motion components: (1) horizontal motion, and (2) vertical expansion or contraction. We measured perceived position misalignment and length misperception in the CLE paradigm, as well as separately for stimuli with the individual motion components of the CLE, as a function of target luminance. Perceived position misalignment and length misperception varied similarly with target luminance, both in the CLE paradigm and when the individual motion components were tested separately. The misperception of stimulus position and length in the CLE reflects an additional processing delay that may be caused by an interaction between the motion components in two directions. […]
Open Access
Age-related synapse loss in hippocampal CA3 is not reversed by caloric restriction
(Pergamon Press, 2010) Adams, Michelle M.; Donohue, H. S.; Linville, M. C.; Iversen, E. A.; Newton, I. G.; Bechtold, J. K. B.
Caloric restriction (CR) is a reduction of total caloric intake without a decrease in micronutrients or a disproportionate reduction of any one dietary component. While CR attenuates age-related cognitive deficits in tasks of hippocampal-dependent memory, the cellular mechanisms by which CR improves this cognitive decline are poorly understood. Previously, we have reported age-related decreases in key synaptic proteins in the CA3 region of the hippocampus that are stabilized by lifelong CR. In the present study, we examined possible age-related changes in the functional microcircuitry of the synapses in the stratum lacunosum-moleculare (SL-M) of the CA3 region of the hippocampus, and whether lifelong CR might prevent these age-related alterations. We used serial electron microscopy to reconstruct and classify SL-M synapses and their postsynaptic spines. We analyzed synapse number and size as well as spine surface area and volume in young (10 months) and old (29 months) ad libitum fed rats and in old rats that were calorically restricted from 4 months of age. We limited our analysis to SL-M because previous work demonstrated age-related decreases in synaptophysin confined to this specific layer and region of the hippocampus. The results revealed an age-related decrease in macular axo-spinous synapses that was not reversed by CR that occurred in the absence of changes in the size of synapses or spines. Thus, the benefits of CR for CA3 function and synaptic plasticity may involve other biological effects including the stabilization of synaptic proteins levels in the face of age-related synapse loss. © 2010 IBRO.
Open Access
Nanomechanical characterization by double-pass force-distance mapping
(Institute of Physics Publishing, 2011) Dagdas, Yavuz S.; Aslan, M. N.; Tekinay, Ayse B.; Güler, Mustafa O.; Dâna, Aykutlu
We demonstrate high speed force-distance mapping using a double-pass scheme. The topography is measured in tapping mode in the first pass and this information is used in the second pass to move the tip over the sample. In the second pass, the cantilever dither signal is turned off and the sample is vibrated. Rapid (few kHz frequency) force-distance curves can be recorded with small peak interaction force, and can be processed into an image. Such a double-pass measurement eliminates the need for feedback during force-distance measurements. The method is demonstrated on self-assembled peptidic nanofibers. © 2011 IOP Publishing Ltd.
Open Access
Selective adhesion and growth of vascular endothelial cells on bioactive peptide nanofiber functionalized stainless steel surface
(Elsevier, 2011) Ceylan, Hakan; Tekinay, Ayse B.; Güler, Mustafa O.
Metal-based scaffolds such as stents are the most preferred treatment methods for coronary artery disease. However, impaired endothelialization on the luminal surface of the stents is a major limitation occasionally leading to catastrophic consequences in the long term. Coating the stent surface with relevant bioactive molecules is considered to aid in recovery of endothelium around the wound site. However, this strategy remains challenging due to restrictions in availability of proper bioactive signals that will selectively promote growth of endothelium and the lack of convenience for immobilization of such signaling molecules on the metal surface. In this study, we developed self-assembled peptide nanofibers that mimic the native endothelium extracellular matrix and that are securely immobilized on stainless steel surface through mussel-inspired adhesion mechanism. We synthesized Dopa-conjugated peptide amphiphile and REDV-conjugated peptide amphiphile that are self-assembled at physiological pH. We report that Dopa conjugation enabled nanofiber coating on stainless steel surface, which is the most widely used backbone of the current stents. REDV functionalization provided selective growth of endothelial cells on the stainless steel surface. Our results revealed that adhesion, spreading, viability and proliferation rate of vascular endothelial cells are remarkably enhanced on peptide nanofiber coated stainless steel surface compared to uncoated surface. On the other hand, although vascular smooth muscle cells exhibited comparable adhesion and spreading profile on peptide nanofibers, their viability and proliferation significantly decreased. Our design strategy for surface bio-functionalization created a favorable microenvironment to promote endothelial cell growth on stainless steel surface, thereby providing an efficient platform for bioactive stent development for long term treatment of cardiovascular diseases. © 2011 Elsevier Ltd.