morphinans and Tremor

A commercial neuroleptanalgesic acepromazine-etorphine combination administered intramuscularly to four horses produced a severe tachycardia and an increase in muscular tone, together with hypoxaemia, hypercapnia, metabolic acidosis associated with an increase in the packed cell volume and hyperglycaemia. No electrolyte changes were found. After reversal of the action of etorphine with diprenorphine, there was a prolonged decrease in the calcium and phosphorus serum concentrations and decreases in the packed cell volume and the total protein serum concentration. In a second experiment on the same four horses, glyceryl guaiacolate (10 g/100 kg body weight intravenously) was given as soon as the horses were anaesthetized with acepromazine-etorphine. The muscular rigidity disappeared and the tachycardia was less evident. There was a more pronounced hypoxaemia but the changes in the other parameters were similar to those in the first experiment. It was concluded that the neuroleptanalgesic-glyceryl guaiacolate combination is not a safe anaesthetic procedure in horses.

Topics: Acepromazine; Anesthesia; Animals; Blood Gas Analysis; Blood Glucose; Calcium; Carbon Dioxide; Drug Combinations; Etorphine; Female; Guaifenesin; Heart Rate; Horse Diseases; Horses; Hydrogen-Ion Concentration; Morphinans; Muscle Rigidity; Neuroleptanalgesia; Oxygen; Potassium; Pulse; Respiration; Time Factors; Tremor

The action of the benzomorphan narcotic antagonists Mr-1452 and Mr-2266 and their respective (+) isomers Mr-1453 and Mr-2267 as well as the antimuscarinic agent atropine upon oxotremorine (OTMN)-induced analgesia, tremor, and hypothermia were investigated in mice. The (+) isomers Mr-1453 (1.0 mg kg-1 i.p.) and Mr-2267 (2.0 mg kg-1 i.p.), but not the (-) isomers (Mr-1452 and Mr-2266) in doses up to 2.0 mg kg-1 i.p. after 30 min pretreatment produced a significant and parallel shift in OTMN's analgesic dose-response line, assessed by the hot plate test (55 degrees C). None of the isomers tested produced any significant change in OTMN induced tremor or hypothermia. This contrasted with atropine (0.5 mg kg-1 i.p.) which antagonized all three pharmacological parameters. The present data indicate that OTMN-induced analgesia in mice may involve a neuronal substrate which, at least partly, differs from those subserving tremor and hypothermia. In addition it supports the notion that cholinergic analgesia exhibits stereospecific sensitivity to the (+) isomers of narcotic antagonists.

Topics: Animals; Atropine; Benzomorphans; Body Temperature; Drug Interactions; Male; Mice; Morphinans; Narcotic Antagonists; Nociceptors; Oxotremorine; Pain; Stereoisomerism; Time Factors; Tremor

Topics: Acepromazine; Analgesics; Animals; Blood Pressure; Bradycardia; Cyclopropanes; Dog Diseases; Dogs; Drug Combinations; Female; Heart Rate; Horse Diseases; Horses; Hypertension; Hypotension; Injections, Intravenous; Male; Morphinans; Narcotic Antagonists; Neuroleptanalgesia; Respiration; Tremor; Vagotomy; Venous Pressure

Topics: Acepromazine; Analgesics; Animals; Cyclopropanes; Drug Combinations; Horses; Immobilization; Morphinans; Neuroleptanalgesia; Respiration; Tachycardia; Tremor

Topics: Abscess; Analgesia; Analgesics; Anesthesia; Animal Population Groups; Animals; Animals, Domestic; Artiodactyla; Body Weight; Drug Combinations; Hypnotics and Sedatives; Immobilization; Injections, Intramuscular; Morphinans; Neuroleptanalgesia; Perissodactyla; Thiazines; Tremor

Topics: Analgesics; Anesthesia, General; Animals; Heart Rate; Horse Diseases; Horses; Male; Morphinans; Respiration; Tremor