title: Preparative surgery enhances the direct spinal actions of three injectable anaesthetics in the anaesthetized rat.
abstract: 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.
authors.affiliation: Department of Physiology, The School of Medical Sciences, University of Bristol, Unirersity Walk, Bristol BS8 1TD U.K.
authors.forename: Nick A
authors.initials: NA
authors.lastname: Hartell
authors.forename: Max P
authors.initials: MP
authors.lastname: Headley
mesh_terms: 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
chemical_list: D000777:Anesthetics; D011277:Pregnanediones; D002698:Chloralose; D007649:Ketamine; C006477:alphaxalone; C033418:alphadolone