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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ablation of tissue surrounding anteroventral third ventricle (AV3V) was studied in three models of hypertensive rats. Lesions were placed in the AV3V at one and six weeks following the initiation of one kidney Grollman renal hypertension. At one week the rise in blood pressure was arrested and water intake was reduced; at six weeks arterial pressure returned to prehypertensive levels in animals surviving the post-lesion hydrational crisis. In two kidney (one clip) Goldblatt animals lesioned two weeks post-clip, arterial pressure was significantly reduced but did not become fully normotensive. Finally, the AV3V was also lesioned in spontaneously hypertensive rats (SHR-Okamoto strain) with established hypertension. The lesion did not reduce arterial pressure in adult SHR although characteristic initial adipsia and weight loss occurred. Ablation of the AV3V thus altered the course of maintenance of renal hypertension; however, the arterial pressure of SHR was not affected.
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PMID:Interruption of the maintenance phase of established hypertension by ablation of the anteroventral third ventricle (AV3V) in rats. 75 72

Several reports have suggested that a central action of the renin-angiotensin system plays a role in the development of renal hypertension. Based on the identification of the anteroventral thrid ventricle (AV3V) as a site of central angiotensin dipsogenic and pressor mechanisms, the present study examined the effect of electrolytic lesions in the AV3V region on the development of renal hypertension in rats. Lesioning alone produced a temporary but profound adipsia and, in one-half of the rats, a substantial transient elevation in arterial pressure. After lesioned rats had recovered normal drinking and blood pressure, unilateral nephrectomy with figure-of-eight wrapping of the remaining kidney failed to produce the hypertension and increased drinking observed after renal wrapping in shamlesioned rats. The possibility that the failure of lesioned rats to increase water intake after wrapping prevents hypertension development was ruled out by experiments demonstrating that normal rats exhibited identical rises in arterial pressure after wrapping regardless of whether or not they were allowed to increase water intake. The fact that unanesthetized lesioned rats exhibit attenuated drinking and pressor responses to systemically administered angiotensin suggests this mechanism as a possible explanation for the failure of AVV-lesioned rats to increase drinking and blood pressure after renal wrapping.
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PMID:Prevention of the development of renal hypertension by anteroventral third ventricular tissue lesions. 85 73

Lesion of the anteroventral portion of the third cerebral ventricle causes hypernatremia, adipsia, and attenuation of the pressor response to intravenous administration of angiotensin II and norepinephrine. In addition, these lesions prevent the development of several experimental models of hypertension. In this study, a lesion of the third cerebral ventricle region was made in 14 dogs. In seven dogs in which hypernatremia developed the lesions included the organum vasculosum of the lamina terminalis; seven animals in which the circumventricular organ was spared by the lesion remained normonatremic. Vascular responsiveness of isolated right carotid artery rings to angiotensin II and phenylephrine was assessed 3 days after lesioning the anteroventral portion of the third cerebral ventricle. In endothelium-denuded ring vessels, vasoconstrictor responses to phenylephrine were significantly decreased in animals both with and without inclusion of the organum vasculosum of the lamina terminalis. A similar effect was observed in intact vessels of dogs in which the circumventricular organ was spared but not in those with lesions that included this area. In contrast, angiotensin II-induced vasoconstriction was significantly decreased in the arteries with intact endothelium of both groups of lesioned animals. These data show that lesion of the anteroventral third ventricle area alters alpha 1-adrenergic and angiotensin II vascular responsiveness in isolated carotid artery rings with the possible participation of the endothelium.
Hypertension 1991 Jul
PMID:Attenuated vascular reactivity in dogs with anteroventral third ventricle lesions. 186 Jul 10

The anteroventral third ventricle (AV3V) region plays an important role in fluid and electrolyte balance and cardiovascular control in the rat; however, experiments in other species have raised questions about the universality of findings in the rat. The effects of discrete lesions placed within the AV3V area on hydromineral balance, the pressor response to angiotensin II given intravenously, and the initiation of a renin-dependent model of hypertension were examined in the dog. A transpharyngeal approach to the optic chiasm enabled us to destroy only the anterior aspects of the AV3V region (aAV3V group) or to include the entire nucleus medianus (NM) as well (aAV3V + NM group). Lesions of the aAV3V caused polydipsia and transient hypernatremia and hyperosmolality. In contrast, adipsia and a sustained increase in plasma sodium levels and osmolality were observed in dogs with lesions of the aAV3V plus the entire NM. Neither lesion altered baseline arterial pressure, heart rate, plasma levels of catecholamines and vasopressin, or total plasma protein levels. Only in aAV3V + NM lesioned dogs was there a tendency for plasma angiotensin II immunoreactivity to be elevated above control values at 2 and 4 days after operation. Neither lesion attenuated the pressor response to intravenous angiotension II or the initiation of renal hypertension induced by aortic coarctation. As observed in other species, structures within the AV3V region participate in hydromineral balance in the dog; however, in the dog portions of the NM dorsal to the AV3V region are essential for the mediation of drinking behavior.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension
PMID:The anteroventral third ventricle region. Participation in the regulation of blood pressure in conscious dogs. 399 35

Ablation of tissue surrounding the anteroventral third cerebral ventricle (AV3V) has been demonstrated to prevent and reverse renal hypertension in the rat. The contribution of this brain area to the maintenance of hypertension in other species has not been examined. In the present investigation, an attempt was made to produce two-kidney, one clip renal hypertension in rabbits with histologically and functionally defined AV3V destruction. Electrolytic lesion of the AV3V in rabbits produced effects closely resembling those previously seen in rats: increased plasma volume and plasma sodium, temporary adipsia, no change in resting arterial pressure or heart rate, and significant attenuation of pressor responsiveness to angiotensin II (AII) delivered intracranially. However, the increase in arterial pressure observed over a 4-week period following the application of a 0.5 mm silver clip to the left renal artery (opposite kidney intact) was identical in 12 AV3V-lesioned and 12 sham-operated rabbits. Hypertension development was not accompanied by significant sodium retention, water retention, or plasma/extracellular fluid volume expansion in either group of rabbits. Pressor responses to intravenous infusions of AII and norepinephrine were identical in sham and AV3V-X rabbits. Thus, destruction of the AV3V, and the attendant reduction in the central pressor action of AII, does not alter the pattern of development of two-kidney, one clip renal hypertension in the rabbit. The contrasting results in rats and rabbits could be explained by the differing contribution of the area postrema to the pressor action of AII in the two species.
Hypertension
PMID:Influence of forebrain periventricular lesions on the development of renal hypertension in rabbits. 706 Nov 22