Antinociception versus serum concentration relationships following acute administration of intravenous morphine in male and female Sprague-dawley rats: Differences between the tail flick and hot plate nociceptive tests

Antinociception versus serum morphine concentration relationships were defined in male and female Sprague-Dawley rats administered single intravenous (i.v.) bolus doses of morphine, using the hot plate (2.1-14 mg/kg) and tail flick tests (1-8 mg/kg).