Abstract
Summary Third cerebral ventricular administration of 1-2 mg of methionine-en-kephalin caused both emesis and hyperther-mia in cats. The emetic response was prevented, and the hyperthermic response was reduced by 100-250 μg of naloxone given intraventricularly 30 min before enkepha-lin. These results provide further evidence that enkephalins can act on opiate receptors in the brain. This investigation was supported by USPHS Research Grant NS 08618.1 would like to thank Ms. Jean Ann Robins for her technical assistance.