The pharmacological properties of the cholinergic false transmitter, N-2-acetoxyethyl-N-methylpyrrolidinium, and its precursor, N-2-hydroxyethyl-N-methylpyrrolidinium.
1 The pharmacological properties of N-2-hydroxyethyl-N-methyl pyrrolidinium (pyrrolcholine) and its acetate ester, recently shown to be a false transmitter at the cholinergic electromotor synapses in Torpedo marmorata, also those of the corresponding morpholinium compounds (morpholinecholine, acetylmorpholinecholine) have been studied on the guinea-pig ileum, frog heart, rectus abdominis muscle, rat blood pressure, rat gastrocnemius muscle and dorsal muscle of the leech. 2 Acetylpyrrolcholine and acetylmorpholinecholine are full cholinoceptor agonists with dose-response curves parallel to that of acetylcholine. They are, however, less potent. Acetylpyrrolcholine is relatively more potent as a muscarinic drug (molar potency about 30% of that of acetylcholine in the ileum but only 4% on the leech) whereas acetylmorpholinecholine is more strongly nicotinic. The unacetylated compounds are very weak agonists with potencies comparable to that of choline. 3 Pyrrolcholine in high concentration showed a distinct neuromuscular blocking effect in the rat gastrocnemius muscle preparation. It is likely that this is a direct effect and not due to uptake by the presynaptic nerve terminals followed by conversion to a false transmitter since it was not reduced by hemicholinium-3, which is known to block uptake of choline and choline analogues by the presynaptic high affinity choline uptake system.
D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001001:Anura; D001794:Blood Pressure / Q000187:drug effects; D002794:Choline / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D007865:Leeches; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000502:physiology; D010525:Peripheral Nerves / Q000187:drug effects / Q000502:physiology; D011758:Pyrroles / Q000494:pharmacology*; D011759:Pyrrolidines; D051381:Rats; D011950:Receptors, Cholinergic / Q000187:drug effects*
D011758:Pyrroles; D011759:Pyrrolidines; D011950:Receptors, Cholinergic; C026168:pyrrolcholine; D002794:Choline; D000109:Acetylcholine