Electrophysiologic effects of galanin on neurons of the central nervous system

The neuropeptide galanin is found in a large number of neurons and nerve terminals throughout the nervous system. In nerve terminals, galanin is contained in large dense-core vesicles and is released upon electrical stimulation. A variety of electrophysiologic studies have examined the effects of galanin application onto neurons of the central nervous system. Overall, galanin appears to have inhibitory effects in the central nervous system, causing in most cases a potassium-mediated hyperpolarization accompanied by a decrease in input resistance. Other actions include a reduction in presynaptic excitatory inputs and an interaction with other applied neurotransmitters. These effects are robust and long lasting in most cases. Differences in the responses mediated by the various receptor subtypes have not been explored electrophysiologically. More complete analysis awaits the availability of more potent and specific receptor anatagonists.