Effects of certain stress situations and of DBS on acetylcholinetransferase, acetylcholinesterase, and monoamineoxidase activities in various regions of brain of juvenile carp, (Cyprinus carpio L.)

Effects of stress situations and of a detergent (DBS) on activities of the cholinergic system enzymes, i.e., acetylcholinetransferase (AChT) and acetylcholinesterase (AChE) as well as on the activity of monoamineoxidase (MAO) in fore-, mid-, and hindbrain of carp juveniles were studied. Both the thermal and immobilisation stresses as well as the detergent were found to cause a slight increase in the AChT activity in midbrain accompanied by a decline of the AChE activity in mid- and hindbrain; on the otber hand, the MAO activity increase, brought about by the detergent, occurred in hindbrain only. The results show the fish cholinergic system activity to be affected by the two stress situations and the detergent contained in the fish habitat. Thus the detergent, apart from its known toxic effects, may act as a stressor to fish.