Effects of cyproheptadine and pizotifen on central muscarinic receptors.
The affinities of cyproheptadine, pizotifen and (+/-)-quinuclidinyl xanthane-9-carboxylate hemioxylate (QNX) were determined at muscarinic autoreceptors and postsynaptic (IP1 formation) receptors in rat hippocampal slices. The affinity values for QNX were 8.2 and 8.5 respectively. Cyproheptadine and pizotifen were less potent than QNX. Pizotifen was slightly (2-fold) less active at antagonizing IP1 formation than blocking the autoreceptors whereas cyproheptadine was equally active at antagonizing the two hippocampal muscarinic receptors.
Richards
M H
MH
Marion Merrell Dow Research Institute, Strasbourg, France.
D000818:Animals; D002490:Central Nervous System / Q000187:drug effects / Q000378:metabolism*; D003533:Cyproheptadine / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D010276:Parasympatholytics / Q000494:pharmacology; D010918:Pizotyline / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects*
D007295:Inositol Phosphates; D010276:Parasympatholytics; D011976:Receptors, Muscarinic; D010918:Pizotyline; D003533:Cyproheptadine