TY - JOUR T1 - Spontaneous regeneration of free muscarinic receptor after alkylation by BM 123. II. Recovery in broken cell preparations. JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 119 LP - 126 VL - 248 IS - 1 AU - J J Waite AU - D J Jenden Y1 - 1989/01/01 UR - http://jpet.aspetjournals.org/content/248/1/119.abstract N2 - Muscarinic receptors from rat cerebral cortex were found to recover from alkylation by the specific ligand N-[-(2-chloroethyl-methylamino)-2-butynyl]-2-pyrrolidone (BM 123) without the benefit of cellular integrity, i.e., in washed membranes incubated at 37 degrees C for relatively long times (days). Unalkylated receptor number increased in alkylated preparations whether viewed as femtomoles per milligram of protein or as a percentage of the atropine-protected control. The rate of recovery was independent of pH over the range 6 to 9 and it was slowed but not eliminated by incubation at 4 degrees C. Muscarinic receptor recovery from BM 123 was linearly dependent on the concentration of alkylated receptors, indicating first-order kinetics and yielding a rate constant 0.026/hr. Of the other chloroethylamines examined for evidence of in vitro muscarinic receptor recovery from alkylation, only one, phenoxybenzamine, exhibited irreversible receptor blockade under these conditions. Each of the others showed different rates for regeneration of free receptors. ER -