Behavioral effects of acute and chronic triazolam treatments in albino rats S.M. Aburawi a, * , A.S. Elhwuegi b , S.S. Ahmed a , S.F. Saad c , A.S. Attia c a Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Great Alfateh University, P.O. Box 84593, Tripoli, Libya b Department of Pharmacology and Toxicology, Faculty of Pharmacy and Health Sciences, Ajman University of Science and Technology Network, Abu Dhabi Campus, Abu Dhabi, P.O. Box 5102, United Arab Emirates c Department of Pharmacology and Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt Received 1 October 2002; accepted 21 April 2003 Abstract Previous behavioral studies on triazolam (TZ), which are small in number, could only speculate about tolerance to the anxiolytic effect of TZ, as the experiments did not cover sufficient time (of 4 to 7 days) for tolerance to develop. Therefore longer time for chronic TZ administration is used. We investigated the effects of TZ on motor activity and exploratory behavior using plus maze and open field. Three experiments were conducted. In the first, five groups of rats were acutely treated with different doses of TZ (0.25 mg/kg-4.0 mg/kg). In the second set of experiments, rats were treated chronically with a single daily dose of TZ (started with 0.25 mg/kg and increased by time to 1.0 mg/kg) for 5 weeks (representing clinical use). In the third, rats were treated chronically with three daily doses of TZ (started with 0.25 mg/kg and increased by time to 0.5 mg/kg) for 20 days (mimicking drug abuse). Acute TZ administration produced dose dependent anxiolytic effects and a decrease in motor activity with higher doses. Chronically treated rats, either once daily or three times daily doses, showed tolerance to both anxiolytic and sedative effects of TZ. It may be concluded that tolerance to the anxiolytic and sedative effects of TZ would develop after chronic administration either with clinical use or its abuse. D 2003 Elsevier Inc. All rights reserved. Keywords: Albino rats; Anxiety; Open field; Plus-maze; Tolerance; Triazolam 0024-3205/$ - see front matter D 2003 Elsevier Inc. All rights reserved. doi:10.1016/S0024-3205(03)00612-X * Corresponding author. Tel.: +218-21-444-9662; fax: +218-21-444-4240. E-mail address: s _ aburawi@hotmail.com (S.M. Aburawi). www.elsevier.com/locate/lifescie Life Sciences 73 (2003) 3095 – 3107