Springer Online Journal Archives 1860-2000
Summary Acetylcholinesterase (AChE) activity in the central nervous system and foot muscle in the garden snail,Cryptozona ligulata, was maximum at 20.00 h and minimum at 08.00 h during the 24 h period of the day. The cyclic variation in acetylcholine (ACh) was out of phase with that of AChE. In the body fluid, ACh content showed a rhythm with maximum at 00.00 h and minimum at 12.00 h, with AChE activity being in phase with it. The rhythm of spontaneous electrical activity of the nervous system was in phase with that of AChE activity in tissues. Perfusion with body fluid collected from snails at 20.00 h elevated the spontaneous electrical activity, while body fluid collected at 08.00 h inhibited the activity. Perfusion with extract prepared from the central nervous tissue isolated at 08.00 h elevated the electrical activity, while the extract prepared from nervous tissue isolated at 20.00 h inhibited the activity. Perfusion with 10−4 M acetylcholine chloride solution elevated the electrical activity. It is suggested that the synthesis and release of ACh occur in a regular diel cycle in tissues. These changes, among others, may be responsible for the observed diurnal rhythmicity in electrical activity in the snail.
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