title: Effects of cyclic nucleotides on mammalian motor nerve terminals.
abstract: This research examined the effects of several cyclic nucleotides on in vivo cat soleus nerves and muscles. The reagents were administered by rapid close intra-arterial injection while electrical activity in single motor axons and contractile activity in the whole muscle were monitored. Cyclic N6-2'-O-dibutyryl adenosine 3',5'-monophosphate (dibutyryl cAMP) initiated bursts of action potentials in unstimulated axons. It also caused the occurrence of stimulus bound repetitive potentials in stimulated axons. It caused the muscle to undergo a series of rapid asynchronous contractions and potentiated the strength of stimulus-evoked contractions. Monobutyryl cAMP produced similar responses, but was less potent than dibutyryl cAMP. cAMP produced only a small, transient depression of neuromuscular transmission. There was no response to dibutyryl cyclic 3',5' guanosine monophosphate or sodium butyrate. None of these reagents affected denervated muscle. The results suggest that cAMP-like materials that can penetrate nerve membranes cause depolarization of motor nerve terminals, prolongation of the depolarization of the terminal initiated by an action potential and release of transmitter.
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects; D003994:Bucladesine / Q000494:pharmacology; D002087:Butyrates / Q000494:pharmacology; D002415:Cats; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D004558:Electric Stimulation; D009046:Motor Neurons / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects; D009121:Muscle Denervation; D009132:Muscles / Q000294:innervation; D009411:Nerve Endings / Q000187:drug effects*; D009712:Nucleotides, Cyclic / Q000494:pharmacology*
chemical_list: D002087:Butyrates; D009712:Nucleotides, Cyclic; D003994:Bucladesine; D000242:Cyclic AMP