Drinking induced by injection of angiotensin into the brain of the rat

Abstract

SUMMARY1. When applied directly to the brain, angiotensin II amide, as either the valine5 or isoleucine5 octapeptide, causes rats in normal fluid balance to drink water.2. The drinking response to angiotensin injections is copious, rapid, repeatable within the same test session, and stable over months of testing in the same animal.3. The response is motivationally potent and specific. After injection the animals move directly to the source of water and drink. There is typically no preliminary hyperactivity or subsequent depression. The animals do not eat, gnaw or exhibit other behaviours that are not normally seen during spontaneous drinking. The injections rouse sleeping animals to drink and interrupt eating in animals deprived of food for two days.4. The region of the brain that is most sensitive to angiotensin includes the anterior hypothalamus, the preoptic region, and the septum including the nucleus accumbens.5. Intracranial renin elicited drinking. Bradykinin and vasopressin did not, nor did adrenaline, noradrenaline or aldosterone. In the most sensitive region, sites positive for angiotensin also yielded drinking to carbachol.6. Responses were obtained with 5 ng (ca. 5 p-mole) and occurred reliably with 50 ng angiotensin or more. The dose-response curve for amount drunk rose from 5 to 100 ng and levelled off thereafter. Angiotensin is therefore the most potent dipsogen known and is effective at doses that are reasonably within the concentration range for circulating endogenous angiotensin.

Changes in the subcellular distribution of NADPH oxidase subunit p47phox in dendrites of rat dorsomedial nucleus tractus solitarius neurons in response to chronic administration of hypertensive agents

“…One area where AngII and phenylephrine produce contrasting effects is in the area of fluid balance. Angiotensin II is a potent dipsogenic agent (13), while centrally infused phenylephrine inhibits drinking induced by central administration of AngII (5). In addition, AngII and phenylephrine also produce differences in neural activation in brain areas involved in fluid homeostasis.…”

Effects of i.c.v. administration of interleukin-1 on sleep and body temperature of interleukin-6-deficient mice

“…After recovery, the patency of the cannula was tested by injection of 250 ng of angiotensin II in 0.5 µl PFS. Angiotensin II induces a drinking a response by stimulating pre-optic structures (Epstein et al, 1970;Denton et al, 1990;Weisinger et al, 1999;Skott, 2003); only data from mice with positive drinking responses were included in subsequent analyses. At least seven days were allowed for recovery after the implantation of the ICV guide cannula before experimental protocols were begun.…”

Intracerebral implantation of carbachol in the rat: Its effect on water intake and body temperature

“…Application of cmbachol in the area preoptica of these rats does not induce drinking whether they are still adipsic or not [36]. Water deprivation as well as the injection of a hypertonie saline solution induce ADH secretion as well as drinking and cholinergic stimulation has been shown to augment ADH secretion [4,11,34,35], but no effect of ADH injections on water intake has been found [1,10] and carbachol induced drinking is hardly ever accompanied by an antidiuresis [19]. Carbachol induced drinking seems, according to the above mentioned data from the literature, not to depend on intraand extracellular dehydration which in itself are strong stimuli to consume water [2,14].…”