UP-REGULATION OF CHOLECYSTOKININ RECEPTORS IN THE NUCLEUS-ACCUMBENS OF THE YOUNG PREHYPERTENSIVE SPONTANEOUSLY HYPERTENSIVE RAT

We employed receptor autoradiography to test the hypothesis that chang es in cholecystokinin neurotransmission in the striatum of the young s pontaneously hypertensive rat (SHR) is involved in the development of hypertension. The binding density of I-125-Bolton Hunter labelled chol ecystokinin octapeptide (I-125-BH-CCK8) in the striatum of 5-week-old prehypertensive SHRs and its normotensive control the Wistar-Kyoto rat (WKY) was determined using computer-assisted densitometry. We found a significant increase in I-125-BH-CCK8 binding density in the nucleus accumbens of the SHR. No difference between the binding density of I-1 25-BH-CCK8 was found in the caudate-putamen and the prefrontal cortex of SHRs and WKYs. These results suggest that changes in CCK8S neurotra nsmission or receptor function are not secondary to an increase in art erial blood pressure and, therefore, may be involved in the developmen t of hypertension.