Enhancement of memory by a cholinesterase inhibitor associated with muscarinic receptor down-regulation.
Rats trained on a passive avoidance task 24 hours following a single intraperitoneal injection of diisopropyl fluorophosphate (DFP, 1.2 mg/kg) showed enhanced retention when tested 7 days later. In a parallel group of rats, reduced cortical [3H] quinuclidinyl benzilate binding was demonstrable 24 hours following DFP administration. The association of reduced muscarinic receptor binding and enhanced performance on a memory task contradicts previous reports which suggested that retention was impaired by treatments which down-regulate muscarinic receptors. This contradiction may be reconciled if pre-synaptic factors such as agonist availability are considered in conjunction with post-synaptic receptor effects.
D000704:Analysis of Variance; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004597:Electroshock; D007531:Isoflurophate / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects*
D002800:Cholinesterase Inhibitors; D011976:Receptors, Muscarinic; D007531:Isoflurophate