Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ganglionic effects of the histamine H2 receptor antagonists cimetidine, ranitidine and 1-nitro-2-(2-propynylamino)-2-(2-[dimethylaminomethyl-2-furanyl) methylthiol]-ethylamino)ethylene (ORF 17578) were compared in the isolated superior cervical ganglion of the rat. Extracellular recording of compound action potentials showed that the drugs caused concentration-dependent inhibition of ganglionic transmission, as indicated by depression of the postganglionic compound action potential. Cimetidine-induced inhibition of ganglionic transmission was stimulus frequency-dependent. Increasing the Ca2+ from 2.2 to 4.4 mM in the bathing solution did not significantly affect the inhibitory actions of these agents. In the series with ranitidine, pretreatment with DFP to inhibit acetylcholinesterase similarly had no significant effect on the depression of the compound action potential by ranitidine. All three agents had little or no effect on nerve conduction in isolated vagi of the rat. The results indicate that all three histamine H2 receptor blockers inhibited ganglionic transmission, but only in large concentrations. The results also suggest that the blocking effect of these drugs was unrelated to their reported anticholinesterase action or to blockade of histamine H2 receptors, which are believed to exist on the presynaptic membrane. It is suggested that the ganglion effect may be due to the action of these agents on the acetylcholine receptor-ion channel complex in the postsynaptic membrane.
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PMID:A comparative study of the actions of histamine H2 receptor antagonists on transmission in the isolated superior cervical ganglion of the rat. 197 Jan 32

Intrahippocampal administration of the histamine H1 receptor antagonist pyrilamine (3.2-32 ug/ side) but not the histamine H2 receptor antagonist cimetidine (1.0-10 microg/side) increased the number of errors in the working memory task with a three-panel runway setup. The increase in working memory errors induced by intrahippocampal 32 microg/side pyrilamine was significantly reduced by concurrent infusion of the histamine H1 receptor agonist 2-pyridylethylamine (3.2 and 10 microg/side). The cholinesterase inhibitor physostigmine ( 1.0 and 3.2 microg/side) and D-cycloserine (0.32 and 1.0 microg/side), the partial agonist at the glycine binding site on the NMDA receptor/channel complex, reduced the increase in working memory errors induced by intrahippocampal 32 microg/side pyrilamine. These results suggest that the hippocampal histaminergic activity via histamine H1 receptor is necessary for normal working memory processes and that the septohippocampal cholinergic activation and positive modulation of the NMDA receptor/channel through activation of the glycine site can alleviate dysfunction of hippocampal histamine H1 receptor-mediated neurotransmission involved in working memory function.
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PMID:Cholinergic and glutamatergic activation reverses working memory failure by hippocampal histamine H1 receptor blockade in rats. 1095 48