Neurotoxic and enzymological effects of codeine in Wistar rat (Rattus norvegicus)

Abstract

Codeine is a naturally occurring opiate drug used for the treatment of pains. There have been reports of codeine abuse in some developing countries like Nigeria, however not much have been done on its effects in mammalian model. This study investigated the effect of codeine on acetylcholinesterase and other enzymological parameters in rat. Seventy-five albino rats procured for the study were divided into five groups, each containing five animals per group. Group, (A) served as the control and was administered normal saline free from the drug. The second (B), third, (C) and fourth (D) groups were given a standard therapeutic doses of 10, 15 and 20 mg/kg of codeine respectively. The drug was administered orally for a period of 20 days followed by 5 days recovery. Blood samples for enzymological parameters were obtained by puncturing the retro-orbital venous sinus of the rats. The brain tissues were later collected for the determination of AChE activity. There were significant concentration and duration dependent increase in the values of lipid peroxidation, AChE, lactate dehydrogenase, sodium adenosine triphosphatase and calcium adenosine triphosphatase in treated rats compared to the control. There were however mixed trends in the values of the studied parameters after the 5-day withdrawal of the drug. Further studies on the mechanisms of reactions of codeine in rat are thus recommended. Codeine altered the studied enzymological parameters which could not return to the control after withdrawal in rats. The use of the drug should be monitored to prevent abuse that may lead to physiological changes in animals.