Temperature Dependence of Muscarinic Acetylcholine Receptor Activation, Desensitization, and Resensitization |
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Authors: | Esam El-Fakahany Elliott Richelson |
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Affiliation: | Departments of Psychiatry and Pharmacology, Mayo Foundation, Rochester, Minnesota 55901, U. S. A. |
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Abstract: | Abstract: The effects of temperature on muscarinic acetylcholine receptor activation, desensitization, and resensitization were studied with the use of intact mouse neuroblastoma cells (clone N1E-115), which have muscarinic receptors that mediate cyclic GMP synthesis. Below 15-20°C, activation or desensitization of muscarinic receptors by carbamylcholine and recovery from desensitization (caused by carbamylcholine at 37°C) did not occur. Above these temperatures, the apparent rates of receptor-mediated cyclic GMP synthesis, desensitization, and recovery of sensitivity increased as the incubation temperature was increased. Arrhenius plots of the data yielded activation energies of 25, 14, and 23 kcal.mol−1 for activation, desensitization, and resensitization, respectively. These data suggest that a certain degree of membrane phospholipid fluidity is required for these processes to occur. |
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Keywords: | Muscarinic receptor Cyclic GMP Densensitization Mouse neuroblastoma |
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