ISSN:
1420-9071
Keywords:
Prazosin
;
tolerance
;
blood pressure
;
rats
;
rabbits
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Prazosin was injected i.v. at a dose of 50 μg/kg every 2 h for 8 h in conscious rats. Its hypotensive action significantly declined. A similar effect was also observed in rabbits pretreated with prazosin (40 μg/kg, i.v.) every 1 h for 4 h. In prazosin-treated rabbits, the total peripheral resistance became less responsive to phentolamine stimulation. Repeated prazosin administration abolished its ability to block receptors in a model of anococcygue muscle contraction after noradrenaline (NA) stimulation. The α-adrenoceptors in anococcygue muscle exhibited lower pD2 to NA and lower pA2 to prazosin in prazosin-treated rats. The results demonstrate that repeated prazosin administration reduces the effectiveness of α-adrenoceptors blockers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01922418
