Characteristics of the galanin-induced depolarization of mudpuppy parasympathetic postganglionic neurons.
The depolarization of mudpuppy parasympathetic cardiac neurons, produced by pressure application of the neuropeptide galanin, has been characterized. The amplitude and duration of the depolarization were dependent on the duration of the galanin application. The amplitude of the depolarization increased with hyperpolarization and the reversal potential determined by extrapolation was approximately +10 mV. The amplitude and time course of the galanin-induced depolarization were not changed by substitution of either manganese or magnesium for extracellular calcium, but were decreased by exposure to 50-100 microM d-tubocurarine. It is proposed that the galanin-induced depolarization results from a receptor-activated, nonselective, cation channel; and further, that the receptor initiating depolarization differs from the galanin receptor mediating hyperpolarizing responses in these parasympathetic neurons.
Konopka
L M
LM
Department of Anatomy and Neurobiology, College of Medicine, University of Vermont, Burlington 05405.
Parsons
R L
RL
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D019004:Galanin; D005726:Ganglia, Parasympathetic / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009337:Necturus / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology*
D010455:Peptides; D019004:Galanin