[Inhibitory effect of intraventricular administration of morphine on the hyperviscosity and elevation of blood pressure induced by stress in the rat].
Experiments were performed on 99 Wistar rats. It was found that hyperviscosity and elevation of blood pressure (BP) could be induced by hanging and restraining conscious rats with their four limbs tied on a frame. These effects were unaffected by bilateral vagotomy. By intravenous injection of propranolol or phentolamine, elevation of BP could be reduced, while stress-induced hyperviscosity could only be reduced by propranolol (i.v.). Stress-induced hyperviscosity and elevation of BP could be inhibited by electroacupuncture applied to the right hind leg or microinjection of morphine into 4th ventricle of the brain. On the other hand, if opiate receptor antagonist naloxone was given into the 4th-ventricle, the stress-induced hyperviscosity and elevation of BP could no longer be inhibited by electroacupuncture. It is suggested that the hyperviscosity and elevation of BP induced by hanging and restraining are mediated by excitatory cardiovascular sympathetic outflow with the result of activation of adrenoreceptors. Activation of the opiate receptors in the hindbrain may be responsible for decrease in stress-induced hyperviscosity and elevation of BP and for the inhibitory effect of electroacupuncture of the right hind leg on stress-induced hyperviscosity and elevation of BP.
Guo
X Q
XQ
Department of Physiology, Shanghai Medical University.
Zhao
Y M
YM
Guo
Z
Z
Liang
Z J
ZJ
D000818:Animals; D001794:Blood Pressure; D001809:Blood Viscosity / Q000187:drug effects*; D015671:Electroacupuncture; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological
D009270:Naloxone; D009020:Morphine; D011433:Propranolol; D010646:Phentolamine