Cyclic guanosine 3':5'-monophosphate accumulation and 45Ca-uptake by rat superior cervical ganglia during preganglionic stimulation.
Repetitive preganglionic nerve stimulation increases cyclic guanosine 3':5'-monophosphate (cGMP) content in rat superior cervical ganglia by a mechanism requiring Ca++ but resistant to blockade by cholinergic receptor antagonists. Similarly, 45Ca-uptake during prolonged preganglionic nerve stimulation is unaffected by hexamethonium or atropine. These findings indicate that nerve stimulation increases cGMP accumulation and 45Ca-uptake by a noncholinergic mechanism Substance P, met-enkephalin and luteinizing hormone-releasing factor have little or no effect on cGMP content. By contrast, bethanechol causes a 3-fold increase in cGMP content and postganglionic cell firing. Thus, as reported by others, muscarinic receptor activation increases ganglionic cGMP[. 4-Aminopyridine causes an increase in cGMP of resting ganglia that requires Ca++ and the nerve terminal is blocked by tetrodotoxin but unaffected by atropine or hexamethonium. Ouabain also increases ganglionic cGMP content by a process that requires Ca++ and the nerve terminals. Like preganglionic nerve stimulation, 4-aminopyridine and ouabain cause cGMP accumulation in the nerve terminals or in the ganglion cells as a consequence of releasing a noncholinergic transmitter. The uptake of Ca++ by ganglion cells is not an adequate stimulus for cGMP accumulation because the nicotinic receptor agonist dimethylphenylpiperazinium increases 45Ca-uptake but has no effect on cGMP formation in ganglia.
D015761:4-Aminopyridine; D000200:Action Potentials / Q000187:drug effects; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000502:physiology*; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D004558:Electric Stimulation; D005728:Ganglia, Sympathetic / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D000631:Aminopyridines; D001626:Bethanechol Compounds; D010455:Peptides; D018723:Bethanechol; D004246:Dimethylphenylpiperazinium Iodide; D010042:Ouabain; D015761:4-Aminopyridine; D006152:Cyclic GMP; D011188:Potassium; D002118:Calcium