Pharmacological studies on the sympathetic nerve-effector mechanisms in the blood vessel.

1. Our previous studies have suggested that the prejunctional supersensitivity to transmural nerve刺激（TNS） develops slowly and later than the postjunctional one to exogenous norepinephrine（NE） and potassium (Tsuru & Uematsu, Japan. J. Pharmacol. 40：273-282, 1986). This suggestion was pursued in the present study.2. Under anesthesia，unilateral preganglionic fiber to the superior cervical ganglion (SCG) was excised and thecontralateral side was left intact as the control. Decentralized and control arteries isolated1, 2,4和8周后decentralization operation.3. Each arterial preparation was incubated with^3 - ne 10^- M for 1hr at 37 c. Changes in intraluminal pressure was monitored and the perfusate wascollected every 2min by a fraction collector. Increase in ^3 - ne overflow from perfused andsuperfused artery by TNS was measured by a liquid scintillation counter. ^3 - ne overflow wasremarkably increased at low frequenies in the artery of 8-weeks decentrali…More zation as compared with the contralateral control arterywhile there was no significant change in the relatively short term decentralization.43 - ne 10 <-8> M for 1hr atc in the absence and in the presence of cocaine 10 <-4> M. There was no significant difference in^3 - ne uptake between the arteries of 8-weeks decentralization and control.5. Catecholamines in theartery and SCG assayed the modified radioenzymatic thin layer chromatographic method. Therewas no significant difference in the content of dopamine，8-weeks decentralization and control - epinephrine between the both arteries and SCG of 86. the present study . whereas catecholamine content in the denervated artery was remarkably decreased.6confirms our previous suggestion that the increment in neurotransmitter release is responsible forsupersensitivity of the chronically decentralized rabbit ear artery to TNS，并suggests that change in stimulus-secretion coupling may be involved although the mechanismremains to be resolved. Less

1. Our previous studies have suggested that the prejunctional supersensitivity to transmural nerve stimulation (TNS) develops slowly and later than the postjunctional one to exogenous norepinephrine (NE) and potassium (Tsuru ＆ Uematsu, Japan. J. Pharmacol. 40: 273-282, 1986). This suggestion was pursued in the present study.2. Under anesthesia, unilateral preganglionic fiber to the superior cervical ganglion (SCG) was excised and the contralateral side was left intact as the control. Decentralized and control arteries were isolated 1, 2, 4 and 8 weeks after decentralization operation.3. Each arterial preparation was incubated with ^3H-NE 10^- M for 1 hr at 37゜c. Changes in intraluminal pressure was monitored and the perfusate was collected every 2 min by a fraction collector. Increase in ^3H-NE overflow from perfused and superfused artery by TNS was measured by a liquid scintillation counter. ^3H-NE overflow was remarkably increased at low frequenies in the artery of 8-weeks decentrali … More zation as compared with the contralateral control artery, while there was no significant change in the relatively short term decentralization.4. ^3H-Norepinephrine uptake experiment was made after incubation with ^3H-NE 10^<-8> M for 1 hr at 37゜c in the absence and in the presence of cocaine 10^<-4> M. There was no significant difference in ^3H-NE uptake between the arteries of 8-weeks decentralization and control.5. Catecholamines in the artery and SCG were assayed by the modified radioenzymatic thin layer chromatographic method. There was no significant difference in the content of dopamine, NE and epinephrine between the both arteries and SCG of 8-weeks decentralization and control, whereas catecholamine content in the denervated artery was remarkably decreased.6. The present study confirms our previous suggestion that the increment in neurotransmitter release is responsible for supersensitivity of the chronically decentralized rabbit ear artery to TNS, and suggests that change in stimulus-secretion coupling may be involved although the mechanism remains to be resolved. Less