AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 4 852-R859, Copyright © 1990 by American Physiological Society
Blood pressure in streptozotocin-treated Brattleboro and Long-Evans rats
K. C. Tomlinson, S. M. Gardiner and T. Bennett
Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, United Kingdom.
The diabetogenic agent streptozotocin (STZ) was injected intraperitoneally
in Long-Evans and arginine vasopressin (AVP)-deficient Brattleboro rats.
Twenty-eight days later both strains had a bradycardia and systolic
hypotension; STZ-treated Brattleboro rats also had diastolic hypotension.
The vasopressin (V1-receptor) antagonist, d(CH2)5[Tyr(Et)]DAVP, had no
effect on resting blood pressure (BP) or heart rate (HR) in either strain
of rat, indicating the relative maintenance of diastolic BP in STZ-treated
Long-Evans rats was not dependent on acute vascular actions of AVP.
Captopril caused a modest hypotension in all groups of rats, indicating
that BP was not differentially dependent on the renin-angiotensin system in
the different groups. In the presence of captopril and the ganglion
blocker, pentolinium tartrate, the AVP-mediated recovery in BP was impaired
in STZ-treated Long-Evans rats. During administration of
d(CH2)5[Tyr(Et)]DAVP and pentolinium, the angiotensin II (ANG II)-mediated
BP recovery was smaller in both groups of STZ-treated rats, indicating that
this abnormality was not likely to be caused by inhibition of renin release
by AVP. The abnormalities in ANG II- and AVP-mediated recovery were
prevented by insulin treatment.
