Psychoactive drug propranolol modulates behavioral, acetylcholinesterase, and oxidative stress parameters in freshwater African Sharptooth Catfish Clarias gariepinus

Abstract

Objective: Propranolol is a beta-blocker psychoactive drug used for the management of high blood pressure, tremors, atrial fibrillation, and migraine headaches. This study investigated the effect of propranolol on behavior, acetylcholinesterase, lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in the brain of African Sharptooth Catfish Clarias gariepinus juveniles.

Methods: A total of 180 African Sharptooth Catfish were exposed to 7.00-, 9.00-, 11.00-, 13.00-, and 15.00-mg/L acute propranolol concentrations and a control (0.00 mg/L) for 24, 48, 72, and 96 h, and the 96-h LC50 value was 9.48 mg/L. For sublethal study, 120 juvenile African Sharptooth Catfish were divided into four groups of 30 fish each and exposed to 1.90-, 0.95-, and 0.47-mg/L propranolol concentrations and a control for 21 d and allowed to recover for 7 d. All the treatment groups and control were set in triplicates, with 10 fish in each. The behavioral changes due to propranolol exposure were monitored by direct observation and scoring during the exposure and withdrawal period. The brains of fish were sampled every week for 4 weeks in order to evaluate the effects of propranolol on acetylcholinesterase, lipid peroxidation, and oxidative stress parameters.

Results: Behavioral changes were evidenced by alterations in swimming rates, air gulping activities, and opercula beats in the propranolol-exposed fish during the acute exposure. Sublethal exposure resulted in a significant decrease in superoxide dismutase and catalase but increase in glutathione peroxidase and reductase values. Significant increase in lipid peroxidation and acetylcholinesterase enzyme levels were observed as exposure duration increased from day 7 compared with the control. The effects of propranolol on the observed parameters appeared to wane after fish withdrawal from the drug for 7 d.

Conclusions: The drug propranolol, as demonstrated by these alterations, may negatively impact nontarget aquatic species and may have ecological consequences.

Keywords: Clarias gariepinus; acetylcholinesterase; behavior; fish brain; oxidative stress; propranolol.