Aims: The effect of chronic ethanol consumption and ethanol withdrawal on serum cholinesterase (ChE) activity was investigated in female Wistar rats.
Methods: Ethanol was administered by a modified liquid diet with 4.8% (v/v) ethanol for 3 days followed by 25 days on a liquid diet in which the ethanol concentration was increased to 7.2%. Control rats were pair-fed with an isocaloric liquid diet not containing ethanol. The blood ethanol concentration and serum ChE activity were measured at the end of the 4.8% ethanol consumption period; after 7, 14 and 35 days of ethanol (7.2%) consumption, and at 24 and 72 h after ethanol withdrawal following ethanol consumption of 35 days.
Results: Daily ethanol consumption of the rats ranged from 11.5 to 14.9 g/kg. Serum ChE activity was found significantly increased from the 3rd day of ethanol (4.8%) consumption. Serum ChE activities of the rats receiving 7.2% ethanol also increased significantly compared with rats ingesting 4.8% ethanol. Blood ethanol levels were measured as 121 and 0.88 mg/dl on the 35th day of ethanol (7.2%) consumption (just before ethanol withdrawal) and after 24 h of ethanol withdrawal, respectively. Increased serum ChE activity (1968 U/l) was still observed (1942 U/l) after 24 h of ethanol withdrawal. ChE activity returned to control levels (501 U/l) after 72 h of ethanol withdrawal. Audiogenic seizures indicating development of physical dependence on ethanol were also observed after 8 h of ethanol withdrawal in another individual group of ethanol-fed rats.
Conclusions: Our results show that serum ChE activity is increased by chronic ethanol consumption in rats and that this increase is affected by ethanol concentration and duration of ethanol ingestion.