Neurotransmitter and neuropeptide modulation of high affinity choline uptake in Limulus brain.
The role of neurotransmitters in the modulation of the sodium-dependent high affinity choline uptake system (HAChUS) of the horseshoe crab, Limulus polyphemus has been investigated utilizing a tissue slice preparation. Choline uptake was significantly decreased by carbachol but unaffected by atropine and d-tubocurarine. The muscarinic agonist oxotremorine decreased choline uptake by 30.4% while the muscarinic antagonist, pirenzepine, increased uptake by 29.6%. Applied in combination, pirenzepine and oxotremorine abolished their individual effects resulting in control values for choline uptake. The non-cholinergic transmitters octopamine and serotonin significantly enhanced choline uptake. The neuropeptide proctolin elicited a 20% increase in choline transport whereas Phe-Met-Arg-Phe (FMRF) amide was without effect. This study demonstrates that neurotransmitters and neuropeptides modulate the HAChUS, possibly through specific receptor-mediated second messenger systems.
Ford
B D
BD
Department of Physiology, Meharry Medical College, Nashville, TN 37208, USA.
Dorsey
W C
WC
Townsel
J G
JG
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001921:Brain / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D002794:Choline / Q000378:metabolism*; D019835:FMRFamide; D006737:Horseshoe Crabs / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism* / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009655:Octopamine / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology; D010890:Pirenzepine / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology; D014403:Tubocurarine / Q000494:pharmacology
D009479:Neuropeptides; D018377:Neurotransmitter Agents; D009842:Oligopeptides; D009655:Octopamine; D012701:Serotonin; D010890:Pirenzepine; C011536:proctolin; D010095:Oxotremorine; D019835:FMRFamide; D001285:Atropine; D002217:Carbachol; D002794:Choline; D011188:Potassium; D014403:Tubocurarine