Breslow M J, Tobin J R, Kubos K L, Raff H, Traystman R J
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205.
Am J Physiol. 1991 Jan;260(1 Pt 2):H21-6. doi: 10.1152/ajpheart.1991.260.1.H21.
The objective of this study was to determine whether three- to fourfold increases in adrenal medullary blood flow (MQ), observed during catecholamine secretion induced by splanchnic nerve stimulation (NS), are necessary for a maximal secretory response. Eight pentobarbital-anesthetized adult male mongrel dogs (25-35 kg) were subjected to two episodes of NS-induced catecholamine secretion. To limit increases in MQ, one NS (20 Hz, 8 V, 1.5 ms) was performed under control conditions, the other was after reduction of adrenal perfusion pressure (PP). PP was 124.8 +/- 6.0 at control and was reduced to 23.0 +/- 1.0 mmHg by inflation of an aortic occluder located 3 in. above the adrenals. NS under control conditions increased ipsilateral MQ (measured using radiolabeled microspheres) from 181 +/- 39 to 1,336 +/- 199 ml.min-1.100 g-1 and adrenal epinephrine secretion from 184 +/- 128 to 11,445 +/- 5,216 ng.min-1.g medulla-1. Contralateral MQ and cortical blood flow were unaffected by NS. Reduction of PP decreased MQ to 32 +/- 6 ml.min-1.100 g-1 and adrenal cortical blood flow from 251 +/- 23 to 25 +/- 6 ml.min-1.100 g-1.PP reduction had no effect on either corticosteroid secretion or unstimulated epinephrine secretion. NS at reduced PP increased ipsilateral MQ to 146 +/- 27 ml.min-1.100 g-1 and epinephrine secretion to 13,935 +/- 5,175 ng.min-1.g medulla-1. These data indicate that epinephrine secretion is not altered when MQ is limited by reduction of PP and suggest that, at normal PP, increases in MQ during catecholamine secretion are not necessary for a maximal secretory response.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是确定在内脏神经刺激（NS）诱导的儿茶酚胺分泌过程中观察到的肾上腺髓质血流量（MQ）增加三到四倍，对于最大分泌反应是否必要。八只经戊巴比妥麻醉的成年雄性杂种犬（25 - 35千克）接受了两次NS诱导的儿茶酚胺分泌实验。为了限制MQ的增加，一次NS（20赫兹，8伏，1.5毫秒）在对照条件下进行，另一次在降低肾上腺灌注压（PP）后进行。对照时PP为124.8±6.0，通过在肾上腺上方3英寸处充气主动脉阻断器，PP降至23.0±1.0毫米汞柱。对照条件下的NS使同侧MQ（使用放射性标记微球测量）从181±39增加到1336±199毫升·分钟⁻¹·100克⁻¹，肾上腺肾上腺素分泌从184±128增加到11445±5216纳克·分钟⁻¹·克髓质⁻¹。对侧MQ和皮质血流量不受NS影响。PP降低使MQ降至32±6毫升·分钟⁻¹·100克⁻¹，肾上腺皮质血流量从251±23降至25±6毫升·分钟⁻¹·100克⁻¹。PP降低对皮质类固醇分泌或未刺激的肾上腺素分泌均无影响。PP降低时的NS使同侧MQ增加到146±27毫升·分钟⁻¹·100克⁻¹，肾上腺素分泌增加到13935±5175纳克·分钟⁻¹·克髓质⁻¹。这些数据表明，当通过降低PP限制MQ时，肾上腺素分泌未改变，提示在正常PP时，儿茶酚胺分泌期间MQ的增加对于最大分泌反应并非必要。（摘要截短于250字）
