APOMORPHINE‐INDUCED AND PILOCARPINE‐INDUCED HYPOTHERMIA IN MICE: DRUG INTERACTIONS AND CHANGES IN DRUG SENSITIVITY AFTER CAUDATE NUCLEUS LESIONS

Abstract

1 Apomorphine and pilocarpine each produced dose-dependent hypothermic effects in mice. However, the dose-response curve for pilocarpine was steeper than that for apomorphine. 2 Bilateral lesions of the caudate nucleus produced a permanent decrease in sensitivity to apomorphine but had no effect on sensitivity to pilocarpine. 3 Apomorphine and pilocarpine had synergistic effects; i.e. the hypothermic effect was greater following a combination of the drugs than following either drug alone. 4 The effect of apomorphine was antagonized by either haloperidol or scopolamine; only scopolamine antagonized the effect of pilocarpine. 5 These results suggest that a mechanism involving dopaminergic neurones in the caudate nucleus has a modulatory role in temperature regulation.