Preparative surgery enhances the direct spinal actions of three injectable anaesthetics in the anaesthetized rat.
In this study we have investigated the influence of preparative surgery on the potency with which a range of injectable anaesthetics depressed nociceptive withdrawal reflexes in anaesthetized, spinalized rats. Drug effects were compared on 2 different preparations, each requiring differing degrees of preparatory surgery. Recordings were made in each case of unitary motoneurone responses to controlled noxious stimuli. The dose-dependent effects of the general anaesthetics alpha-chloralose (20-80 mg/kg i.v.) and alphaxalone/alphadolone (0.5-2 mg/kg) and of the dissociative anaesthetic ketamine (0.5-16 mg/kg) were studied. When the degree of surgical intervention was increased, the reflex response to a uniform mechanical pinch stimulus was facilitated. This enhanced response was more susceptible to the reflex depressant actions of all the compounds studied.
Hartell
Nick A
NA
Department of Physiology, The School of Medical Sciences, University of Bristol, Unirersity Walk, Bristol BS8 1TD U.K.
Headley
Max P
MP
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000777:Anesthetics / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D002698:Chloralose / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D009619:Nociceptors / Q000187:drug effects; D010812:Physical Stimulation; D011277:Pregnanediones / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*; D013514:Surgical Procedures, Operative
D000777:Anesthetics; D011277:Pregnanediones; D002698:Chloralose; D007649:Ketamine; C006477:alphaxalone; C033418:alphadolone