The effect of sequential alpha and beta adrenoceptor blockade on mean arterial pressure (MAP) and arterial pressure lability (APL) was studied 3 and 15 days after sino-aortic deafferentation (SAD) in rats. 2. Prazosin, an alpha-1 adrenoceptor blocker, injected iv (1 mg/kg) into SAD rats 3 days after surgery produced a significant fall in MAP (-61 vs -21 mmHg) and APL (-7 vs 0 mmHg) when compared with sham-operated rats. 3. Propranolol, a beta-1 and -2 adrenoceptor blocker, injected iv (1 mg/kg) after prazosin into SAD rats (3 days) produced a significant increase in MAP (+37 vs +5 mmHg) and APL (+4 vs 0 mmHg) when compared with sham-operated rats. 4. Prazosin injected iv (1 mg/kg) into SAD rats 15 days after surgery produced smaller changes in MAP than observed in rats 3 days after SAD but a significant fall in MAP (-35 vs -13 mmHg) when compared with sham-operated rats. At this phase of SAD, no changes in APL were observed after prazosin. 5. Propranolol injected iv (1 mg/kg) after prazosin into SAD and sham-operated rats (15 days) produced no changes in MAP and APL. 6. Prazosin injected into SAD rats (3 and 15 days) with previous adrenal demedullation produced falls in MAP and APL similar to those observed in SAD rats with intact adrenals. 7. In contrast to SAD rats with intact adrenals, propranolol injected after prazosin into SAD rats (3 days) with previous adrenal demedullation produced no increase in MAP. 8. These results suggest that a) alpha-1 adrenoceptors are directly involved in MAP maintenance in SAD rats 3 and 15 days after surgery; b) 2 weeks after SAD, compensatory reflex mechanisms may be acting to reduce the fall in MAP produced by prazosin; c) alpha-1 adrenoceptors are not directly involved in APL generation; d) APL is related to the activation of beta adrenoceptors by endogenous epinephrine release.
摘要
研究了大鼠去窦主动脉神经支配（SAD）后3天和15天，序贯性α和β肾上腺素能受体阻断对平均动脉压（MAP）和动脉压波动度（APL）的影响。2. 对术后3天的SAD大鼠静脉注射α1肾上腺素能受体阻滞剂哌唑嗪（1mg/kg），与假手术大鼠相比，MAP（-61 vs -21 mmHg）和APL（-7 vs 0 mmHg）显著下降。3. 对术后3天的SAD大鼠，在注射哌唑嗪后静脉注射β1和β2肾上腺素能受体阻滞剂普萘洛尔（1mg/kg），与假手术大鼠相比，MAP（+37 vs +5 mmHg）和APL（+4 vs 0 mmHg）显著升高。4. 对术后15天的SAD大鼠静脉注射哌唑嗪（1mg/kg），与术后3天的大鼠相比，MAP变化较小，但与假手术大鼠相比，MAP仍显著下降（-35 vs -13 mmHg）。在SAD的这个阶段，注射哌唑嗪后未观察到APL的变化。5. 对术后15天的SAD大鼠和假手术大鼠，在注射哌唑嗪后静脉注射普萘洛尔（1mg/kg），MAP和APL均无变化。6. 对术前已进行肾上腺髓质切除的SAD大鼠（术后3天和15天）注射哌唑嗪，MAP和APL下降，与肾上腺完整的SAD大鼠相似。7. 与肾上腺完整的SAD大鼠不同，对术前已进行肾上腺髓质切除的SAD大鼠（术后3天），在注射哌唑嗪后注射普萘洛尔，MAP未升高。8. 这些结果表明：a）术后3天和15天，α1肾上腺素能受体直接参与维持SAD大鼠的MAP；b）SAD后2周，代偿性反射机制可能在减轻哌唑嗪引起的MAP下降；c）α1肾上腺素能受体不直接参与APL的产生；d）APL与内源性肾上腺素释放激活β肾上腺素能受体有关。
