A COMPARATIVE STUDY IN THE CAT OF THE RESPIRATORY EFFECTS OF MORPHINE INJECTED INTRAVENOUSLY AND INTO THE CEREBROSPINAL FLUID

摘要: Experiments were performed on cats anesthetized with Dial-urethane. Respiration was recorded plethysmographically and end-expiratory CO2 monitored continuously. Morphine sulfate injected i.v. through cannulas inserted stereotactically into the third fourth ventricles bulbar subarachnoid space. in ventricle space (10-50 µg 50 µl) induced respiratory depression qualitatively similar to that obtained after injection (1 mg/kg). Elevation percent accounted for primarily by reduction of frequency. After injection, beginning peak effect appeared earlier than slightly more effective ventricle. On other hand, morphine (50 elicited an immediate stimulation followed a second phase during which frequency remained elevated but tidal volume progressively reduced increased. Analysis relationship between response data showed depressant any appropriate routes characterized elevation apneic point slope above resting level. Injection then tended restore curves toward normal phase.