Influence of repeated prazosin administration on cardiovascular responses in rats and rabbits |
| |
Authors: | S -C G Hui B S Qiu |
| |
Institution: | (1) Studies in Biomedical and Health Science, School of Professional, and Continuing Education, Knowles Building, The University of Hong Kong, Pokfulam Road, Hong Kong;(2) Shantou University Medical College, (China) |
| |
Abstract: | Prazosin was injected i.v. at a dose of 50 g/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 g/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 -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 -adrenoceptors blockers. |
| |
Keywords: | Prazosin tolerance blood pressure rats rabbits |
本文献已被 SpringerLink 等数据库收录! |
|