Effects of nonpeptide V1a and V2 antagonists on blood pressure fast oscillations in conscious rats.
This paper describes the effects of vasopressin nonpeptide selective V1a (OPC-21268) and V2 (OPC-31260) antagonists on fast blood pressure (BP) oscillations in conscious non-haemorrhaged and haemorrhaged rats. Equidistant sampling at 20 Hz allowed direct spectral analysis of BP on 30 overlapping 2048 point-time series. In non-haemorrhaged rats, V1a antagonist (5 mg/kg; i.v) reduced BP and low-frequency (LF-BP) component while subsequent administration of V2 antagonist (1 mg/kg; i.v) reversed these changes and enhanced the very low-frequency (VLF-BP) component. In haemorrhaged rats (5-15 ml/kg/min) V2 antagonist pre-treatment enhanced the VLF-BP component during normotensive bleeding, while the V1a antagonist pre-treatment modified BP variability after hypotensive haemorrhage by enhancing the HF-SBP component. The results suggest that under normotensive conditions vasopressin by the stimulation of both V1a and V2 receptors buffers BP variability in the VLF-BP frequency domain. In addition, under hypotensive conditions vasopressin, by the stimulation of V1a receptors buffers the respiration-induced HF-BP oscillation.
Japundzic-Zigon
N
N
Department of Clinical Pharmacology and Toxicology, Medical Faculty, Belgrade. zigon@necker.fr
D000704:Analysis of Variance; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006470:Hemorrhage / Q000503:physiopathology*; D020896:Hypovolemia / Q000503:physiopathology; D008297:Male; D010880:Piperidines / Q000494:pharmacology*; D015363:Quinolones / Q000494:pharmacology*; D051381:Rats; D017483:Receptors, Vasopressin / Q000502:physiology
D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines; D010880:Piperidines; D015363:Quinolones; D017483:Receptors, Vasopressin; C068644:OPC 21268; C076251:mozavaptan