Medullary kappa hyperalgesic mechanisms II. The effects of ethylketazocine administered into the fourth cerebral ventricle of the conscious dog.

Ethylketazocine (EKC) (2 micrograms/100 microliter/min for 15 min) was infused into the fourth cerebral ventricles of conscious dogs. The drug produced hyperalgesia, respiratory depression, miosis, increased EEG electrogenesis and behavioral sedation. Hyperthermia and tremulousness were observed in some animals. These pharmacologic effects reflect the action of EKC on pontomedullary periventricular sites which control nociception, autonomic function and arousal.