1989 Volume 14 Issue 2 Pages 124-129
To study the relationship between the sympathetic nerve and catecholamine in blood pressure mainntenance, we gave normotensive rats a single intraperitoneal injection of 100mg/kg or 240mg/kg of 5-hydroxydopamine (5-OHDA) which acts to chemically block the sympathetic nerve. The rats’ blood pressures and heart rates were continuously measured through the caudal artery. After the administration of 5-OHDA, the blood pressures showed a biphasic pattern of fluctuation: a marked transient rise and fall followed after 2 days by gradual recovery. The heart rates decreased to large extent after 5-OHDA administration, but rapidly returned its initial levels. Moreover, the blood pressures and heart rates showed dose-dependent responses to 5-OHDA.
This suggests that 5-OHDA might substitute for and discharge endogenous noradrenaline in amine strage granules at the end of the sympathetic nerve, and that 5-hydroxynoradrenaline, a metabolite of 5-OHDA, might act as a false neurotransmitter substance.
