Neurohypophysial peptides depress cholinergic transmission in a mammalian sympathetic ganglion.
The actions of arginine-vasopressin (AVP) and oxytocin (OXT) were investigated in the rat superior cervical ganglion (SCG). At micromolar concentrations AVP decreased the amplitude of fast excitatory postsynaptic potentials (f-EPSPs) evoked by preganglionic stimulation and in many cells depolarized the postsynaptic membrane. Both effects were reversibly abolished by a potent vasopressor antagonist. The peptide decreased the frequency of spontaneous miniature EPSPs and the quantal content of the f-EPSPs without affecting the sensitivity of the ganglion cells to acetylcholine. OXT exerted the same effects as AVP but was less powerful. It was concluded that neurohypophysial peptides exert a dual pre- and post-synaptic action mediated by specific receptors.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D005728:Ganglia, Sympathetic / Q000187:drug effects*; D010121:Oxytocin / Q000494:pharmacology*; D010275:Parasympathetic Nervous System / Q000187:drug effects*; D051381:Rats; D013569:Synapses / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects*
D001127:Arginine Vasopressin; D010121:Oxytocin