This study set out to assess the neurobehavioral effects of subchronic, oral bromocriptine methanesulfonate using the open field and the Y-maze in healthy male mice. Sixty adult Swiss albino mice were assigned into three groups. Controls received normal saline, while test groups received bromocriptine methanesulfonate at 2.5 and 5？mg/kg/day, respectively, for a period of 21 days. Neurobehavioral tests were carried out on days 1 and 21 after administration. Open field assessment on day 1 after administration revealed significant increase in grooming at 2.5 and 5？mg/kg, while horizontal and vertical locomotion showed no significant changes. Day 1 also showed no significant changes in Y-maze alternation. On day 21, horizontal locomotion, rearing, and grooming were increased significantly at 2.5 and 5？mg/kg doses after administration; also, spatial memory was significantly enhanced at 2.5？mg/kg. In conclusion, the study demonstrates the ability of oral bromocriptine to affect neurobehavior in normal mice. It also suggests that there is a cumulative effect of oral bromocriptine on the behaviors studied with more changes being seen after subchronic administration rather than after a single oral dose. 1. Introduction Bromocriptine is an ergot derivative of ergoline and also an amide derivative of the d isomer of lysergic acid; it is a white, crystalline almost odorless powder [1]. Bromocriptine is absorbed largely from the gastrointestinal tract, having a half life of about 3.3 hours and reaching peak plasma levels within 1-2 hours after oral administration. Excretion is usually through bile and faeces [2]. Bromocriptine is a dopamine agonist that exerts its actions and properties at striatal D1 and D2 adenyl cyclase-linked dopamine receptors [3]. Bromocriptine inhibits prolactin secretion [4] and also inhibits glutamate release by reversing the glutamate GLT1 transporter [5]. Bromocriptine is used in the treatment of Parkinson’s disease and has also been found valuable in the treatment of a number of endocrinologic and gynaecologic disorders [2, 6]. It also induces behavioral and hormonal changes that could last several hours following a single systemic dose [7], such behavioral changes include motor hyperactivity in animals. In May 2009, bromocriptine mesylate quick release was approved for the treatment of type 2 diabetes; it is believed to exert its antidiuretic actions from its influence on hypothalamic circadian neuronal activities thus resetting abnormally elevated hypothalamic drive for an increase in plasma glucose, free fatty acids, and triglycerides
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