Effect of cholinergic drugs on acute and chronic morphine dependence

The effect of both centrally and peripherally acting cholinergic drugs on acute and chronic morphine dependence was investigated. The quaternary ammonium drugs, neostigmine and atropine methyl bromide which cross the blood-brain barrier with difficulty, significantly altered the withdrawal jumping and wet shakes in a similar manner to that exhibited by centrally acting tertiary drugs viz. physostigmine and atropine sulphate. The cholinergic agonists inhibited the withdrawal signs while the antagonists enhanced the same. This suggests that the peripheral cholinergic mechanisms are also involved apart from the central mechanisms in the phenomena of acute and chronic morphine dependence.