| Abstract: | The respiratory depression in rats induced by sc ohmefentanyl showed a ceiling effect, but a linear relation with log dose when applied into the dorsal medulla. It elicited, however, a marked excitation on respiration when applied to dorsal pons. This excitatory effect of ohmefentanyl was antagonized by naloxone, and it antagonized to some extent the respiratory depressant effect induced by ohmefentanyl itself applied on dorsal medulla. It was postulated that the respiratory excitatory effect of sc ohmefentanyl on dorsal pons may have a bearing on the ceiling effect of its respiratory depression. |
