Koyama S, Terada N, Shiojima Y, Takeuchi T
Jpn J Physiol. 1984;34(6):995-1002. doi: 10.2170/jjphysiol.34.995.
In anesthetized dogs, intravenous infections of 30 micrograms/kg of leucine- and methionine-enkephalin (L- and M-enk respectively) produced a significant reduction of mean blood pressure (MPB) and heart rate (HR). The peak decreases in MBP and HR occurred within 1 min after injection and recoveries to pre-injection levels within 3 min. The depressor responses to both L-enk and M-enk were abolished by intracisternal pretreatment with yohimbine (0.5 mg/kg) but not with prazosin (0.1 mg/kg). Pretreatment with either drug did not alter the bradycardia. All cardiovascular effects of both L-enk and M-enk were prevented by intravenous pretreatment with naloxone (2 mg/kg). These results suggest that central alpha 2-adrenoceptors may participate in the central actions of enkephalins on blood pressure regulation. HR responses to enkephalins may be elicited by a different mechanism.
在麻醉犬中，静脉注射30微克/千克的亮氨酸脑啡肽和甲硫氨酸脑啡肽（分别为L-脑啡肽和M-脑啡肽）可使平均血压（MPB）和心率（HR）显著降低。MPB和HR的峰值降低在注射后1分钟内出现，并在3分钟内恢复到注射前水平。用育亨宾（0.5毫克/千克）脑池内预处理可消除对L-脑啡肽和M-脑啡肽的降压反应，但用哌唑嗪（0.1毫克/千克）预处理则不能。用这两种药物预处理均不改变心动过缓。静脉注射纳洛酮（2毫克/千克）预处理可防止L-脑啡肽和M-脑啡肽的所有心血管效应。这些结果表明，中枢α2-肾上腺素能受体可能参与脑啡肽对血压调节的中枢作用。脑啡肽对HR的反应可能由不同机制引发。
