1995 年 18 巻 9 号 p. 1207-1210
The effects of yohimbine and desipramine on adrenal catecholamine (CA) release in response to splanchnic nerve stimulation (SNS) were examined in anesthetized dogs. SNS at 1 and 3Hz produced frequency-dependent increases in epinephrine (EPI) and norepinephrine (NE) output determined from adrenal venous blood. Yohimbine (30 and 100μg/kg, i.v.), a selective α2-adrenoceptor antagonist, enhanced the SNS-induced increases in both EPI and NE output. Desipramine (100 and 300μg/kg, i.v.), an amine pump inhibitor, enhanced the SNS-induced increases in NE output, whereas no enhancement of EPI output was produced. After desipramine treatment, yohimbine further enhanced the SNS-induced increases in EPI and NE output. After yohimbine treatment, desipramine further enhanced the SNS-induced increase in NE output. These results suggest that the release of adrenal CA in response to SNS is inhibited by α2-adrenoceptors, and that released NE, rather than EPI, is predominantly taken up into the dog adrenal medullary cells.