Abstract
We studied the effects of vasoactive intestinal polypeptide (VIP) on the cholinergic synaptic transmission that was developed between rat sympathetic neurons in culture. Electrophysiological examinations revealed that the amplitude of fast excitatory postsynaptic potential (fast EPSP) was increased by VIP (0.2–0.8 μM) reversibly and dose-dependently, whereas transient nicotinic depolarization evoked by pressure application of acetylcholine (ACh) was not affected by VIP. In most of the cells examined, VIP depolarized membrane potential by a few millivolts with concomitant increases in membrane conductance. Furthermore, the VIP-induced depolarization was suppressed by Co 2+ but not by hexamethonium or atropine. Hence it is highly likely that the peptide augmented the amplitude of fast EPSPs by increasing ACh release from the presynaptic cell. These results demonstrate that VIP influences the presynaptic phase of cholinergic synaptic transmission between sympathetic neurons.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
