Effect of atropine and/or physostigmine on cerebral acetylcholine in rats poisoned with Soman

Abstract

Cerebral acetylcholine (ACh) levels in normal animals were found to be 29.6 ± 1.4 (S.E.) nmoles ACh/g of wet tissue. Physostigmine and Soman reduced cerebral cholinesterase (ChE) activity to < 18% of control and increased cerebral ACh levels by 148 and 130% of normal, respectively. Neostigmine failed to alter ChE activity or ACh levels. Atropine decreased ACh levels to 62% of normal. When atropine was given with physostigmine or Soman, the ACh levels were almost normal. Soman failed to increase the levels of ACh in animals protected with atropine and physostigmine. When physostigmine was followed by Soman, cerebral ACh levels were lower than in animals given physostigmine only. Our data indicate that it may be possible to manage ACh concentrations in animals poisoned with irreversible ChE inhibitors by prior treatment with apprópriate dosages of anticholinergic and reversible anti-ChE drugs. The data also suggest that ACh and/or anti-ChEs inhibit the synthesis of ACh.