A method for very rapid determinations of catechols using ion-pairing reverse phase HPLC with electrochemical detection: Effects of L-DOPA treatment on the catechol content in various rat brain structures

Ehrenström, Fredrik; Johansson, Pehr

doi:10.1016/0024-3205(85)90211-5

Cited by 40 publications

(12 citation statements)

References 17 publications

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“…To our knowledge, the time course of formation and degradation of DA metabolites after L-dopa + benserazide treatment in rat striatum has not been studied in this way before. Ehrenstrom & Johansson (1985), using a similar LC-ECD method, noticed in the striatum of L-dopatreated rats that the highest concentration of DA (+137%) was obtained after 30min and the maximal increase in DOPAC levels (+370%) occurred after 60 min. They also investigated three other DA metabolites (salsolinol, norsalsolinol and epinine) and reported the presence of an unknown peak on the chromatograms from treated rats.…”

Section: Discussionmentioning

confidence: 93%

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Re-evaluation of the L-dopa loading effect on dopamine metabolism in rat striatum

Gemayel

Trouvin

Prioux-Guyonneau

et al. 1986

Journal of Pharmacy and Pharmacology

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Investigation by HPLC with electrochemical detection of dopamine (DA) metabolism in rat striatum after L-dopa + benserazide treatment allowed quantification of the time course evolution of DA, 3,4-dihydroxyphenylacetic acid and homovanillic acid levels. Furthermore, four peaks which did not appear in controls, were detected in treated striatum. One was identified as 3-methoxytyrosine, the level of which was still high 9 h after treatment. 3-Methoxytyrosine, has been detected previously in plasma of parkinsonian patients treated with L-dopa, and the disturbance in DA metabolism could explain some of the side-effects induced by that treatment.

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Section: Discussionmentioning

confidence: 93%

“…On the chromatograms, in addition to the known peaks, other compounds can be co-eluted and investigated. With these methods, several authors have studied the L-dopa loading effect on the dopamine (DA) metabolism in various tissues (Hefti et a1 1981;Beers et a1 1984;Ehrenstrom & Johansson 1985).…”

mentioning

confidence: 99%

Re-evaluation of the L-dopa loading effect on dopamine metabolism in rat striatum

Gemayel

Trouvin

Prioux-Guyonneau

et al. 1986

Journal of Pharmacy and Pharmacology

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“…These levels are surprisingly high since the hypothalamic content of EPI is low and ranges from 17 to 40 pg/mg wet tissue [25][26][27]. The EPI content of the hypothalamus ranges from 340 to 800 pg, the mean weight of the hypothalamus being 20 mg.…”

Section: Discussionmentioning

confidence: 99%

Epinephrine in Rat Hypophysial Portal Blood Is Derived Mainly from the Adrenal Medulla

et al. 1990

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This study was performed to determine if epinephrine (EPI) present in hypophysial portal blood has a peripheral or a central origin. Pituitary stalk and femoral arterial EPI plasma levels were simultaneously measured in rats anesthetized with thiopental or urethane. EPI was measured by two different methods: radioenzymatic assay or HPLC followed by electrochemical detection. In thiopental-anesthetized rats, levels were higher in hypophysial portal than in femoral arterial plasma with both methods. In urethane-anesthetized rats, no difference in EPI concentrations was found between peripheral and portal plasma. A rapid blood volume depletion (15 ml/kg in 3 min) evoked a marked elevation of pituitary stalk and arterial EPI plasma concentration while norepinephrine (NE) and dopamine (DA) levels were unaffected. Under both types of anesthesia, the increase of EPI levels was higher in peripheral than in portal plasma. After removal of the adrenal glands, EPI was undetectable or barely detectable in pituitary stalk and arterial plasma. The hemorrhage-induced stimulation of EPI secretion was blunted in portal and peripheral plasma of adrenalectomized rats. These findings indicate that: (1) hypophysial portal EPI plasma concentration is highly dependent on an adrenal source; (2) hypothalamic EPI is not released into portal circulation in response to acute hemorrhage, and (3) anesthesia markedly influences catecholamines plasma levels.

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“…The extent of denervation was determined by measuring NE concentrations in spleen, liver, and small intestine using HPLC with electrochemical detection. Extraction of catecholamines was performed, as described previously (8). Tissue samples weighing between 120 and 160 mg were diluted to a final volume of 1 ml with 0.2 M perchloric acid (PCA).…”

Section: Experimental Protocolsmentioning

confidence: 99%

Sympathetic innervation of the splanchnic region mediates the beneficial hemodynamic effects of 8-OH-DPAT in hemorrhagic shock

Tiniakov

Pahan

Scrogin

2012

American Journal of Physiology-Regulatory, Integrative and Comp

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Administration of the 5-HT(1A) receptor agonist, 8-OH-DPAT, improves cardiovascular hemodynamics and tissue oxygenation in conscious rats subjected to hypovolemic shock. This effect is mediated by sympathetic-dependent increases in venous tone. To determine the role of splanchnic nerves in this response, effects of 8-OH-DPAT (30 nmol/kg iv) were measured following fixed-arterial blood pressure hemorrhagic shock (i.e., maintenance of 50 mmHg arterial pressure for 25 min) in rats subjected to bilateral splanchnic nerve denervation (SD). Splanchnic denervation decreased baseline venous tone as measured by mean circulatory filling pressure (MCFP) and accelerated the onset of hypotension during blood loss. Splanchnic denervation did not affect the immediate pressor effect of 8-OH-DPAT but did reverse the drug's lasting pressor effect, as well as its ability to increase MCFP and improve metabolic acidosis. Like SD, adrenal demedullation (ADMX) lowered baseline MCFP and accelerated the hypotensive response to blood withdrawal but also reduced the volume of blood withdrawal required to maintain arterial blood pressure at 50 mmHg. 8-OH-DPAT raised MCFP early after administration in ADMX rats, but the response did not persist throughout the posthemorrhage period. In a fixed-volume hemorrhage model, 8-OH-DPAT continued to raise blood pressure in ADMX rats. However, it produced only a transient and variable rise in MCFP compared with sham-operated animals. The data indicate that 8-OH-DPAT increases venoconstriction and improves acid-base balance in hypovolemic rats through activation of splanchnic nerves. This effect is due, in part, to activation of the adrenal medulla.

show abstract

A method for very rapid determinations of catechols using ion-pairing reverse phase HPLC with electrochemical detection: Effects of L-DOPA treatment on the catechol content in various rat brain structures

Cited by 40 publications

References 17 publications

Re-evaluation of the L-dopa loading effect on dopamine metabolism in rat striatum

Re-evaluation of the L-dopa loading effect on dopamine metabolism in rat striatum

Epinephrine in Rat Hypophysial Portal Blood Is Derived Mainly from the Adrenal Medulla

Sympathetic innervation of the splanchnic region mediates the beneficial hemodynamic effects of 8-OH-DPAT in hemorrhagic shock

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