Charles Rappoport ou la crise du marxisme en France

Goldberg, Harvey E.

doi:10.3406/homso.1972.1519

Cited by 7 publications

(10 citation statements)

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“…Thus, it is possible to definitively demonstrate specific antagonism with appropriate doses of haloperidol, phenothiazines, and bulbocapnine and to distinguish between dopamine-like vasodilation and vasodilation caused by activation of other receptors (12,14). Furthermore, under appropriate experimental conditions, similar vasodilation does not occur in the phenoxybenzamine-treated femoral vascular bed, thus, permitting separation of dopamine-like compounds from other types of vasodilators (1). Availability of this model and the relatively rigid analogs of dopamine has enabled us to determine the preferred conformation for activation of dopamine and (B2-adrenergic vascular receptors.…”

Section: Discussionmentioning

confidence: 99%

Conformational requirements for dopamine-induced vasodilation.

Volkman¹,

Kohli²,

Goldberg³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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ABSIRACT The availability of a series of semi-rigid analogs of dopamine and epinine has made it possible to investigate the conformational requirements for action on dopamine and 2-adrenergic vascular receptors. The analogs were screened for dopamine-agonist action by intra-arterial injections into the renal vascular bed and for P2-adrenergic activity by similar injections into the femoral vascular bed in dogs pretreated with phenoxybenzamine. 2-Amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene and its N-methyl derivative (analogous to the trans P rotamer of dopamine) exhibited pronounced dopamine-agonist activity and minimal 02-adrenergic activity. In contrast, the semi-rigid analog of the trans a rotamer of dopamine (2-amino-5,6-dihydroxy-1,2,3,4-tetrahydronaphthalene; A-5,6-DTN) and its N-methyl derivative exerted pronounced #2-adrenergic activity but were inactive as dopamine agonists.6,7-Dihydroxytetrahydroisoquinoline,a semirigid analog of the cis P rotamer of dopamine, did not produce renal vasodilation. These results indicate that a conformation of dopamine similar to that found in A-6,7-DTN is required for dopamine-vascular activity, while the conformation found in A-5,6-DTN is preferred for interaction with #2-adrenergic receptors. Dopamine can cause vasodilation by several mechanisms (1).Vasodilation can be induced directly by action on 32radrenergic or dopamine vascular receptors (2) and indirectly by action on receptors in autonomic ganglia (3, 4) and postganglionic sympathetic nerves (5, 6). Because the dopamine molecule is flexible and can assume a variety of conformations, it has not been possible to determine whether a specific conformation is required for each of these diverse actions. A possible approach to this problem has been provided recently by the demonstration that a semi-rigid analog of dopamine, 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (A-6,7-DTN), met all the criteria of a dopamine agonist in the canine renal and mesenteric vascular beds (7). Because the side chain of the dopamine moiety contained within A-6,7-DTN is fixed in a fully extended position with the amino group trans to the phenyl ring, these results suggested that this conformation of dopamine (trans ,B rotamer) may be required for activation of dopamine receptors. However, dopamine can exist in yet another trans conformation (trans a rotamer) as in 2-amino-5,6-dihydroxy-1,2,3,4-tetrahydronaphthalene , in which the phenyl ring has undergone a 1800 rotation about the phenyl-C-1 bond (see Fig. 1). Previous studies with certain derivatives of A-5,6-DTN indicated that they exert dopamine-like activity in the central nervous system, because they are potent emetic agents and produce gnawing behavior in mice (8, 9). Some of these analogs have also been shown to produce typical (32-adrenergic actions (10).Accordingly, we have compared the relative ,32-adrenergicThe costs of publication of this article were defrayed in part by the payment of page charges from funds made available to support the research which is the su...

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Section: Discussionmentioning

confidence: 99%

Conformational requirements for dopamine-induced vasodilation.

Volkman¹,

Kohli²,

Goldberg³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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“…This vasodilation is most advantageous in some types of shock. It occurs in the coronary, cerebral, mesenteric and, most critically, in the renal vascular beds (GOLDBERG, 1972). The dopamine-induced vasodilation is antagonized, or at least attenuated, by phenothiazine-type drugs (GOLDBERG & YEH, 1971) and by butyrophenones (YEH et al, 1969).…”

Section: Please Scroll Down For Articlementioning

confidence: 99%

“…The dopamine-induced vasodilation is antagonized, or at least attenuated, by phenothiazine-type drugs (GOLDBERG & YEH, 1971) and by butyrophenones (YEH et al, 1969). The 0, adrenoceptors in the myocardium are actm upon directly by dopamine as well as indirectly through the release of norepinephrine from the peripheral nerve endings by dopamine and through the partial metabolism of dopamine to norepinephrine (GOLDBERG, 1972). If sufficiently large doses of dopamine are administered, the cy1-agonistic (vasoconstrictor) effects are apparent.…”

Section: Please Scroll Down For Articlementioning

confidence: 99%

“…If sufficiently large doses of dopamine are administered, the cy1-agonistic (vasoconstrictor) effects are apparent. Therefore, the arteries and veins in all vascular beds are constricted with dopamine when large doses are given (GOLDBERG, 1972). Dopamine-induced diuresis is secondary to the renal vascular dilation when it is given in doses of 1 to 2 mcg kg-' min-' (GOLDBERG, 1972).…”

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confidence: 99%

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Overview of shock

Majerus

1984

Archives Internationales de Physiologie et de Biochimie

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“…Exogenous dopamine (DA) produces a natriuretic/diuretic response in a variety of species, including humans (1,2). The natriuretic effects of DA are generally thought to be due to an increase in renal blood flow and glomerular filtration rate (1) but may include direct tubular effects since low doses of DA increase urine output and urinary sodium excretion without altering renal hemodynamics (3)(4)(5).…”

mentioning

confidence: 99%

Characterization of a dopamine receptor (DA2K) in the kidney inner medulla.

Huo

Healy

1991

Proc. Natl. Acad. Sci. U.S.A.

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Dopamine (DA) produces a natriuretic/diuretic response in the kidney by mcnisms that are still not well understood. There is some ination that DA2 receptors may be involved in mating the effects of DA, but little is known regarding the nature of this receptor in the kidney. Autoraigaphic localation of [3Hspiperone, a DA2 anta t, i ed that high-density binding was r ic to inner meduilary ting ducts (IMCDs) Exogenous dopamine (DA) produces a natriuretic/diuretic response in a variety of species, including humans (1, 2). The natriuretic effects of DA are generally thought to be due to an increase in renal blood flow and glomerular filtration rate (1) but may include direct tubular effects since low doses of DA increase urine output and urinary sodium excretion without altering renal hemodynamics (3-5). Although the mechanism of action ofDA within the kidney is not resolved, the effects ofDA on the kidney are blocked by DA receptor antagonists (2, 6, 7). DA receptors have been classified in the central nervous system as D1 and D2 (8) and in the periphery as DA1 and DA2 (9). A great deal of evidence indicates that vascular and tubular DA1 receptors are involved in mediating the actions of DA on the kidney (6, 7). Further support for a tubular site ofaction for DA comes from autoradiographic localization of DA1 receptors in rat kidney, which indicates that the highest levels are found in the proximal tubules (10, 11).Much less is known regarding the role of DA2 receptors in mediating the renal responses to DA. Spiperone, a central nervous system D2 antagonist, blocks the DA-stimulated increase in renal blood flow and sodium excretion in isolated perfused rat kidney (4). Bromocriptine, a DA2 agonist, has been reported to increase renal blood flow and singlenephron glomerular filtration rate in the rat (12,13

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Charles Rappoport ou la crise du marxisme en France

Cited by 7 publications

References 0 publications

Conformational requirements for dopamine-induced vasodilation.

Conformational requirements for dopamine-induced vasodilation.

Overview of shock

Characterization of a dopamine receptor (DA2K) in the kidney inner medulla.

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