Effects of Propranolol on the Cardiovascular Responses to Intracranial Pressure Elevation in Rats

貝他拮抗劑對顱內壓升高引起心血管變化之影響

蔡美玲(Mei-Ling Tsai) ； 王炳惠(Biing-Huey Wang)

《The Chinese Journal of Physiology》 31卷2期 (1988/12) Pp. 113-124

摘要

本實驗之目的乃藉着引發不同程度之顱內壓觀察腦血流所受之影響，並探討貝他拮抗劑(propranolol)對此一反應的影響。利用人工腦脊髓液灌流至側腦室，將顱內壓自7 mmHg提高至60 mmHg，以雷射血流計連續記錄腦血流之變化。此一顱內壓上升的效應促使腦血流減少，並引發血壓上升，心跳變快，將顱內壓下降至原程度，則血壓上升，心跳變快之現象即可恢復，但是腦血流卻產生先增加後下降的現象。若在顱內壓上升之前給予貝他拮抗劑則顱內壓上升所引發之心跳變快會受到抑制，顱內壓恢復至原程度所產生的腦血流增加的現象也減少，但是腦血流的減少卻不受影響。由此等結果可推測由腦缺血所引發之腦血流增加的結果可因貝他拮抗劑之存在而弱化。

並列摘要

Tsai, M.L. and B.H. Wang: Effects of propranolol on the cardiovascular responses to intracranial pressure elevation in rats. Chinese J. Physiol. 31(2): 113-124, 1988. This study was performed to examine the effects of propranolol on the cardiovascular responses to intracranial pressure (ICP) elevation in rats. Intracranial pressure was raised by infusion of artificial cerebrospinal fluid into a lateral ventricle of rat's brain. Graded increases in ICP (from base line 7 mmHg 40 mmHg and then 60 mmHg) produced a graded reduction in regional cerebral blood flow (measured with a laser Doppler flowmeter at the parietal lobe). The ICP was claimed at each level for 5 min. ICP elevation also produced an incrase in both mean arterial pressure and heart rate. Furthermore, 5 min after the termination of ICP elevation, a rebounding cerebral hyperemia was observed in control rats. It was found that pretreatment of aminals with an i.p. does of 2 mg/kg of propranolol significantly reduced both the tachycardia induced by ICP elevation and the cerebral post-ischemic hyperemia. However, the hypertension induced by ICP elevation was not affected by propranolol. The results suggested that beta-adrenergic mechanisms maybe involved in the cardiovascular responses to ICP elevation.

並列關鍵字

active hyperemia ； cerebral ischemia ； propranolol ； tachycardia ； hypertension