[The effect of the intracerebroventricular administration of vasopressin on the arterial pressure and heart rate of Brattleboro and Long-Evans rats].

Abstract

Vasopressin (VP) was administered in the lateral cerebral ventricles of homozygous rats with congenital diabetes insipidus of Brattleboro (BB) strain as well as of normal animals of Long Evans strain (LE). The following parameters were studied: the latent period for achievement of maximal pressor response in seconds (LP), absolute value of the increase in arterial pressure in comparison with the initial V mmHg (delta AP) and cardiac frequency (CF). The initial values of AP in BB were lower than those values found in LE (BB-9, 10 +/- 0.57 kPa; LE-11, 31 +/- 0.53 kPa; p less than 0.01, while CF showed higher values in BB (350 +/- 8.5 min-1); LE (321 +/- 10 min-1); p less than 0.05. VP, administered intraventricularly, induced quick transitory elevation of AP in both groups, which did not differ substantially both in respect to LP (BB-55 +/- 11 s; LE-43 +/- 6.9) and also in respect to delta AP (BB-3.64 +/- 0.34; LE-3.14 +/- 0.62). CF was not changed in BB (347 +/- 8.9), while it was slightly increased in LE (334 +/- 11). The data show that exogenously administered VP affect the central VP-dependent mechanisms for regulation of AP in the same way in both groups of rats.