[Comparison of the effects of naloxone hydrochloride and methiodide on endotoxic shock in the anesthetized rat].

In the anesthetized rats, both naloxone hydrochloride and methiodide produced transient hypotension and bradycardia. The hydrochloride salt was able to revert (during 1 hr for the dose of 10 mg/kg I.V.) the hypotension produced by the endotoxin of Escherichia coli, the methiodide salt was ineffective. Further naloxone hydrochloride, produced tachycardia and some awaking of the animals which were not observed after the quaternary ammonium salt. These observations strengthen the view that the effects of naloxone observed in the shocked rat are of central origin and that the antihypotensive action results--partly at least--from the antagonism of beta endorphin released by the toxin.