The central muscarinic transmission during anaesthesia and recovery--the central anticholinergic syndrome.

Clinically relevant aspects of the muscarinic transmission in the CNS are mentioned. This transmission depends on the action of acetylcholine (ACh) on the muscarinic receptor and has been better elucidated than the CNS-cholinergic transmission subserved by the nicotinic receptor. Sub-types of the muscarinic receptor have been demonstrated. They are involved in many functions of the CNS. Therefore, disturbance of the CNS muscarinic transmission by ACh-antagonists or lack of ACh results in a colorful but unpredictable behavioural syndrome which is known as the central anticholinergic syndrome (CAS). To a certain degree, the CAS follows all forms of general anaesthesia. It can be prevented or treated by physostigmine which can elevate ACh-levels in the CNS. Postoperative restitution of the CNS-muscarinic transmission results in appropriate behavioural functioning early recovery. Normalization of ACh in the CNS also enhances analgesia and helps to sustain adequate breathing, heart rate and cardiovascular tone.