Vasoactive intestinal polypeptide modulates GABAA receptor function in bipolar cells and ganglion cells of the rat retina.
1. The effect of vasoactive intestinal polypeptide (VIP) on bipolar cells and ganglion cells freshly dissociated from the rat retina was studied under voltage clamp with the use of patch-clamp recording in the whole-cell configuration. 2. Application of VIP (1-100 microM) by itself resulted in no detectable current response in either bipolar cells or ganglion cells. However, gamma-aminobutyric acid (GABA)-activated macroscopic current responses elicited in both neuronal populations were potentiated on superimposed exposure to the neuropeptide. 3. GABA-activated chloride currents and muscimol-induced current responses were similarly potentiated on exposure to VIP, suggesting a synergistic interaction between VIP and GABAA receptor mechanisms. 4. We postulate that VIP plays a neuromodulatory role by regulating the excitability of inner retinal neurons and in this way modulates the efficacy of synaptic transmission in the retina.
Veruki
M L
ML
Program in Neuroscience, University of Rochester School of Medicine and Dentistry, New York 14642.
Yeh
H H
HH
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D018118:Chloride Channels; D004357:Drug Synergism; D004553:Electric Conductivity / Q000187:drug effects; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D018118:Chloride Channels; D007473:Ion Channels; D008565:Membrane Proteins; D011963:Receptors, GABA-A; D009118:Muscimol; D014660:Vasoactive Intestinal Peptide; D005680:gamma-Aminobutyric Acid