MORPHINE-METABOLISM IN THE NATURALLY MORPHINE-TOLERANT AFGHAN PIKA - A PRELIMINARY-STUDY

The afghan pika (Ochotona refescens), a lagomorph which is naturally tolerant to the analgesic action of morphine, metabolizes morphine into morphine 3-glucuronide apparently faster than does the rabbit, another lagomorph which is however normally responsive to morphine. In the two species, following morphine administration, another unidentified component appears very soon (5 min) in pika blood plasma and much later (60 min) in rabbit blood plasma. This unknown component which appers not to be morphine derived might be involved in the natural resistance of the Afghan pika to morphine. © 1990.