THE CHARACTERIZATION OF OXOTREMORINE-INDUCED HYPOTHERMIC RESPONSE IN THE RAT

Oxotremorine is a muscarinic receptor agonist that induces a variety o f physiological and behavioural effects including hypothermia in mice. These effects are antagonized dose-dependently by classical anticholi nergic compounds such as atropine. Although the oxotremorine-induced h ypothermic response has been demonstrated in mice, few studies of the effects of this muscarinic agonist have been made in the rat. The foll owing studies were made in male Sprague Dawley rats: 1. an investigati on of the dose-response relationship between oxotremorine and hypother mia; 2. an examination of the effect of housing on the oxotremorine-in duced hypothermic response, and 3. an investigation of the acute admin istration of various doses of atropine sulphate on the hypothermia cau sed by oxotremorine. The results indicate that the dose-response relat ionship between oxotremorine and the antagonism of hypothermia is simi lar in rat as it is in mice. The results also showed that this effect did not occur in group-housed animals.