Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Smooth muscle cells from the gastric antrum of the rabbit were isolated using collagenase and pronase. We examined the characteristics of muscarinic receptors that control contraction of the muscle cell: kinetics, stoichiometry and specificity of both contractile response to muscarinic agents and binding of labeled N-methyl-scopolamine. Cells contracted in the presence of muscarinic agents after a short time (30 sec) while binding of (3H)-NMS reached a plateau after 10 min exposure. Specific binding was saturable and Scatchard analysis revealed a single class of high-affinity binding sites (Kd: 0.5 nM). Oxotremorine was the most potent agonist with an ED50 of 0.6 pM; acetylcholine and carbachol were 10 times less potent. Muscarinic antagonists competed with (3H)-NMS for binding with IC50 values in the same range (nanomolar or less) than those obtained for inhibition of acetylcholine-induced contractions. Pirenzepine antagonized contractile effect of muscarinic agonists with EC50 in a micromolar range. Intracellular levels of cyclic AMP were lowered by muscarinic agonists. Monoclonal anti-muscarinic receptor antibodies M-35 displayed agonist-like activities triggering contraction and lowering cyclic AMP levels of the cells. However, although the antagonist inhibits M-35-induced contractions and cAMP decrease, M-35 had no effect on binding of the antagonist to the muscarinic receptor. These data revealed the presence of an M2-muscarinic receptor subtype involved in the contractile response of the isolated smooth muscle cell.
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PMID:Muscarinic receptors in isolated smooth muscle cells from gastric antrum. 283 78

The actions of acetylcholine and cholinergic ligands have been studied using dorsal midline neurones from the rnetathoracic ganglion of the cockroach Periplaneta americana.Both nicotine and oxotremorine depolarized dorsal midline neuronal cell bodies.Dose-response curves for nicotine and oxotremorine saturated at different levels. Nicotine-induced depolarizations were completely or partially blocked by mecamylamine, d-tubocurarine, strychnine, and bicuculline, but were insensitive to alpha-bungarotoxin(100 nM), atropine (100 micronM),Scopolamine (10 micronM), and pirenzepine (50 micronM). Following pretreatment with collagenase, the dorsal midline neurones were sensitive to high doses of alpha-bungarotoxin (3 micronM). Oxotremorine-induced depolarizations were blocked by scopolamine (10 micronM) atropine (100 micronM), and pirenzepine (50 micronM) and were insensitive to mecamylamine (10 micronM) and d-tubocurarine (100 micronM). The results indicate the coexistence of at least two distinct acetylcholine receptors on dorsal midline neuronal cell bodies in the cockroach metathoracic ganglion.
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PMID:Acetylcholine receptors of thoracic dorsal midline neurones in the cockroach, Periplaneta Americana. 2131 80