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)

The antitumor agent caracemide [N-acetyl-N-(methylcarbamoyloxy)-N'-methylurea] has been observed to induce signs of cholinergic activation in both animal and human studies at high clinical and toxic levels. The present study was designed to further characterize the ability of caracemide to inhibit cholinesterase both in vivo and in vitro. Caracemide produced a time-dependent inhibition of purified acetylcholinesterase, pseudocholinesterase and rat brain homogenate cholinesterase with IC50 values of 0.60, 0.55 and 17.8 microM, respectively, at the maximal time point of inhibition. Analysis of Lineweaver-Burke plots derived from inhibition of brain homogenates revealed predominantly competitive type inhibition at both initial and maximal incubation times. Intravenous administration of caracemide to rats resulted in a dose-dependent inhibition of brain cholinesterase activity, with the greatest inhibition occurring in the cortex.
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PMID:In vivo and in vitro cholinesterase inhibitor property of the antitumor agent caracemide. 233 10

Because the antitumor drug caracemide causes neuropsychiatric effects in patients, we investigated its effects on the neurochemistry of cultured neuroblastoma cells (murine clone N1E-115). The drug caused a transient elevation in the level of [3H]cyclic GMP that was not blocked by receptor antagonists or by desensitization of histamine or muscarinic receptors. The EC50 for the response to caracemide was 635 microM. Preincubation of cells with caracemide led to the inhibition of muscarinic receptor-mediated [3H]cyclic GMP formation with an IC50 of 450 microM. Caracemide inhibited basal guanylate cyclase activity in homogenates noncompetitively with a Ki value of 162 microM. The drug also inhibited sodium nitroprusside-stimulated guanylate cyclase in homogenates. Caracemide did not inhibit basal adenylate cyclase activity in either intact cells or homogenates, but inhibited adenylate cyclase activated by prostaglandin E1 (PGE1) or forskolin. The muscarinic receptor-mediated reduction of PGE1-stimulated [3H]cyclic AMP formation was not affected. The Ki for the inhibition of PGE1-activated adenylate cyclase in homogenates was 110 microM. Caracemide was a competitive inhibitor of acetylcholinesterase with a Ki value of 8 microM. The drug did not inhibit, but slightly stimulated, monoamine oxidase activity in N1E-115 cells. The results indicate that caracemide can affect several neurochemical systems in neural cells in culture in a way that correlates with its neuropsychiatric effects. The N1E-115 clone thus appears to be useful for evaluating some of the molecular pharmacological effects of drugs interacting with the nervous system.
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PMID:Effect of the antitumor drug caracemide on the neurochemistry of murine neuroblastoma cells (clone N1E-115). 287 11