Cardiac nociception induced rectal response: relation with haemodynamic changes.
Epicardial application of nicotine (200 micrograms/ml) over the left ventricle or occlusion of the left anterior descending coronary artery (LAD) in lightly anaesthetised cats resulted a biphasic change in rectal motility-initial relaxation followed by contraction along with biphasic changes of blood pressure (B.P.) with epicardial nicotine and only hypotension with LAD occlusion. Desensitisation of ventricular receptors by epicardial application of 2% lignocaine abolished the rectal response and the biphasic blood pressure response but not the LAD occlusion induced hypotension. Sectioning of left inferior cardiac nerve (LICN) abolished such cardiorectal reflex but not the B.P. changes. Stimulation of central cut end of LICN elicited similar cardiorectal reflex keeping the B.P. unaltered. Atropinization (1 mg/kg) abolished only the contractile phase of the cardiorectal reflex and also the hypotension induced by epicardial nicotine. Intra-arterial NG-nitro-L-Arginine (LNNA) at a dose of 2 mg/kg abolished the relaxation phase of such cardiorectal reflex keeping the B.P. changes unaltered. LAD occlusion induced hypotension was neither counteracted by atropine nor by LNNA pretreatment. These indicate that though the cardio-rectal reflexes are associated with B.P. changes, they do not have any direct correlation.
Koley
J
J
Department of Physiology, University College of Science, Calcutta.
Basak
A K
AK
Das
M
M
Koley
B
B
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002415:Cats; D003331:Coronary Vessels / Q000502:physiology / Q000601:surgery; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D007022:Hypotension / Q000503:physiopathology; D008297:Male; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D019335:Nitroarginine / Q000494:pharmacology; D009619:Nociceptors / Q000502:physiology*; D010496:Pericardium / Q000187:drug effects / Q000502:physiology; D012007:Rectum / Q000098:blood supply / Q000502:physiology*; D016277:Ventricular Function, Left / Q000187:drug effects
D018722:Nicotinic Agonists; D019335:Nitroarginine; D009538:Nicotine; D001285:Atropine