Regional haemodynamic effects of recombinant murine or human leptin in conscious rats.
Regional haemodynamic responses to recombinant murine or human leptin were assessed in conscious, chronically-instrumented, male, Long-Evans rats (350 - 450 g). Human, but not murine, leptin caused a slight hindquarters vasoconstriction, but neither peptide had any effect on mean arterial blood pressure or heart rate. In the presence of the beta(2)-adrenoceptor antagonist, ICI 118551, a hindquarters vasoconstrictor response to human leptin was not seen, and there was a tachycardia, as there was to murine leptin. The nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester, (L-NAME), did not influence the cardiovascular effects of murine or human leptin. The results indicate that the previously reported sympathoexcitatory effects of murine leptin in anaesthetized rats are not manifest as regional haemodynamic changes in conscious rats, and this is not due to beta(2)-adrenoceptor-mediated vasodilator mechanisms opposing any vasoconstrictor responses. Moreover, the ability of L-NAME to unmask a pressor effect of murine leptin in anaesthetized rats may not be apparent in the conscious state.
Gardiner
S M
SM
School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH.
Kemp
P A
PA
March
J E
JE
Bennett
T
T
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001775:Blood Circulation / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003243:Consciousness; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006614:Hindlimb / Q000098:blood supply; D006801:Humans; D007668:Kidney / Q000098:blood supply; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D008643:Mesentery / Q000098:blood supply; D051379:Mice; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D011994:Recombinant Proteins / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D004791:Enzyme Inhibitors; D020738:Leptin; D011412:Propanolamines; D011994:Recombinant Proteins; C026777:ICI 118551; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester