Tsunoda K, Lee X P, Watanabe S, Doge K, Akiya Y, Watanabe T
Department of Legal Medicine, Showa University School of Medicine Tokyo, Japan.
Nihon Hoigaku Zasshi. 1993 Jun;47(3):193-201.
An attempt was made to determine sex differences in the effects of beta-endorphin (beta-EP) on respiratory and cardiovascular systems using Wistar rats. By the intracerebroventricular administration of beta-EP (0.18 mg/kg) to normal male and female rats, respiratory rate (RR), heart rate (HR) and mean arterial blood pressure (MABP) were depressed significantly (p < 0.01 or 0.001) and CO2 in expired gas increased significantly (p < 0.01). These suppressive effects of the peptide were transiently blocked by the intravenous injection of naloxone (0.2 mg/kg). No differences in the effects of beta-EP between estrous and diestrous female rats could be detected. The effects of the peptide were significantly stronger in RR, HR and MABP for females than for males (0.001 < p < 0.05). Testectomized rats showed suppressive effects of the peptide to the same extent as intact females, but the effects in ovariectomized rats did not differ from those for intact females. In testectomized and ovariectomized rats treated with testosterone, the former showed the same results as intact males, but not the latter. The suppressive effects of beta-EP on the respiratory and cardiovascular systems are thus remarkably relieved by androgen in male rats.
本研究旨在利用Wistar大鼠确定β-内啡肽（β-EP）对呼吸和心血管系统影响的性别差异。通过向正常雄性和雌性大鼠脑室内注射β-EP（0.18mg/kg），呼吸频率（RR）、心率（HR）和平均动脉血压（MABP）显著降低（p<0.01或0.001），呼出气体中的二氧化碳显著增加（p<0.01）。静脉注射纳洛酮（0.2mg/kg）可短暂阻断该肽的这些抑制作用。在发情期和动情间期的雌性大鼠中未检测到β-EP作用的差异。该肽对雌性大鼠RR、HR和MABP的作用明显强于雄性大鼠（0.001<p<0.05）。去势大鼠对该肽的抑制作用与完整雌性大鼠相同，但卵巢切除大鼠的作用与完整雌性大鼠无差异。在用睾酮治疗的去势和卵巢切除大鼠中，前者的结果与完整雄性大鼠相同，而后者则不同。因此，雄性大鼠体内的雄激素可显著减轻β-EP对呼吸和心血管系统的抑制作用。
