EFFECT OF KETANSERIN ON MONOAMINES AND NEUROPEPTIDE-Y IN BRAIN AND PERIPHERAL-TISSUES OF NORMOTENSIVE (WKY) AND SPONTANEOUSLY HYPERTENSIVE (SHR) RATS

The effect of one intraperitoneal (i.p.) injection of ketanserin (K) ( 20mg/kg) on the levels of monoamines and neuropeptide Y (NPY) in some central and peripheral tissues was examined in normotensive (WKY) and spontaneously hypertensive (SHR) rats, In WKY rats, K induced a deplet ion of norepinephrine (NE) in the hypothalamus, the medulla, the atria and the caudal artery together with a decrease in dopamine level (DA) in the hypothalamus and in serotonin level (5-hydroxytryptamine, 5-HT ) in the medulla. The reduction reached 25% to 35%. In SHR, NE and DA levels in the hypothalamus, and NPY levels in the caudal artery were l ower than in WKY, while NE was higher in the adrenals. After treatment with K, NE, 5-HT, 5-HIAA (5-hydroxyindoleacetic acid) and NPY in the medulla were increased by about 30% to 50% while NE in the caudal arte ry was reduced by about the same value as in WKY. These results indica te that K-induced release of monoamines is not linked to NPY release. Moreover, monoamine and NPY sensitivity to K differ in SHR and WKY rat s.