Mechanical Pain Induced-Acute Stress Attenuates Mental Alertness And Behaviour In Wistar Rats

¹Olorunfemi O.J.^*, ²Ajah A.A., ³Ngaikedi C.N., ⁴Asara A.A.
Department of Human Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, University of Port Harcourt, Choba, Port Harcourt, Nigeria.

A B S T R A C T
The study was carried out to ascertain the effects of induced-acute stress on mental alertness and behaviour in rats using Navigational maze task, Elevated maze task, Light/dark box task, Analgesic-metre (paw-withdrawal) task, Open field task. Twenty albino wistar rats were acquired. After two weeks of acclimatization, the rats were weighed and divided into four groups (groups 1, 2, 3, and 4) of five rats in each group. While group 1 received only feed and water serving as the control group, group 2 had their tails clipped during cognitive function test. Group 3 received 0.1ml/150 body weight of rat of a standard drug (epinephrine) administered intraperitonally. Group 4 received a 0.1ml/150body weight of rat of a standard drug (Dopamine) administered intraperitonially. From the observations obtained, it showed that alertness and fine motor coordination and balance were significantly (p<0.05) enhanced by catecholamine drugs, they were also significantly (p<0.05) decreased by physical stress. All forms of stress demonstrated a significant (p<0.05) anti-anxiolytic effect. Stress can be an essential adaptive mechanism needed for survival and with only transient changes in the brain, while others can cause overreaction and deregulation of the hypothalamic pituitary adrenal (HPA) axis thus inflicting detrimental effects on the brain structure and function. Therefore, stress can be either negative or positive modulator of the cognitive functions, which includes learning and memory.
Keywords: mental alertness, Analgesic-metre, Navigational maze task, cognitive function test, Elevated maze task.