Wyniki wyszukiwania

1

Inhibition of potassium-induced ciliary reversal in Fabrea salina by inorganic and organic calcium channel blockers

100%

Dryl S., Lopatowska A.

Acta Protozoologica

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1990

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tom 29

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nr 3

2

Influence of nifedypine on the hyperalgesic action of duodenal distention in sheep

100%

Kania B. F., Lewicki S.

Polish Journal of Veterinary Sciences

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2007

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tom 10

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nr 4

The aim of this study was to determine the influence of nifedypine – competitive antagonist of voltage-gated dependent L-type Ca2+ channels (VGCCs) – on inhibition of reticulo-ruminal motility, heart beats, respiratory rates and other nociceptive behavior symptoms caused by duodenal distention (DD). The animals, which were under general anesthesia, had duodenal and ruminal fistulas and intracerebroventriculary (i.c.v.) cannulas inserted into the lateral ventricle. Reticulo-ruminal contractions were recorded mechanographically using an electronic tensometer. The frequency of reticulo-ruminal contractions was determined by the number of mechanograms with 5 min intervals prior to and after DD (for 180 min).The duodenal distention was performed using a rubber balloon (10 cm length), which was inserted via the duodenal fistula and filled with 40 ml water. Five min DD caused immediate and almost complete inhibition of reticulo-ruminal contractions, nociceptive behavior symptoms, tachycardia and hyperventilation. Nifedypine per se did not change the reticulo-ruminal motility, general behavior or clinical symptoms; however, doses of 1 and 2 mg of nifedypine in toto infused i.c.v 10 minutes before DD prevented all signs of reticulo-ruminal disorders, as well as the general nociceptive behavior. Nifedypine inhibited particularly clinical symptoms such as tachycardia and hyperventilation. The observed antinociceptive action of VGCCs type-L blockers suggests that these channels play a crucial role in the modulation of acute visceral hyperalgesia. Nifedipine can be useful in controlling acute visceral pain associated, for example, with different kinds of colic.

3

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Calcium channel blockers impair the pituitary-adrenocortical responses to central adrenergic receptors stimulation

100%

Borycz J., Bugajski A. J., Gadek-Michalska A., Bugajski J.

Journal of Physiology and Pharmacology

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1993

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tom 44

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nr 2

4

Nitric oxide in the adrenergic- and CRH-induced activation of hypothalamic-pituitary-adrenal axis

100%

Gadek-Michalska A., Bugajski J.

Journal of Physiology and Pharmacology

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2008

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tom 59

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nr 2

In this report we investigated the effect of 7-nitroindazole (7-NI), a specific neuronal inhibitor of nitric oxide synthase (nNOS) and L-NAME, a nonselective NOS inhibitor upon the adrenergic- and CRH-induced stimulation of the hypothalamic-pituitary-adrenal axis in nonanesthetized rast. 7-NI given i.p. and L-NAME administered i.c.v. considerably reduced ACTH and corticosterone secretion induced by phenylephrine (30 µg i.c.v.), an alpha1-adrenergic receptor agonist. These inhibitors also diminished the HPA response to isoprenaline (20 µg i.c.v.), a nonselective ß-adrenergic receptor agonist, and i.c.v. L-NAME significantly lowered the ACTH and corticosterone response to clenbuterol (10 µg i.c.v.), a selective ß2-adrenergic agonist. L-NAME abolished the noradrenaline (NA), an alpha- and ß-receptor agonist-evoked ACTH and corticosterone response, which was reversed by pretreatment with i.p. L-arginine, an endogenous NO substrate. 7-NI abolished the stimulatory action of corticotropin-releasing hormone (CRH 1 µg/kg i.p.) on ACTH but not corticosterone secretion. L-NAME only moderately diminished the CRH-induced ACTH secretion, suggesting that a major part of the CRH-induced HPA axis activation is of neuronal origin. Dihydropyridine, nifedipine, a specific L-type Ca2+ channel blocker, inhibited significantly the CRH-induced ACTH and corticosterone response in rats exposed to 3 days crowding stress but not in rats under basal conditions. This finding indicates the strategic importance of Ca2+ influx into the pituitary corticotrops to meet increased secretory requirement under stressful conditions. Collectively, our results point to complex functional relationship between NO, adrenergic agents CRH and Ca2+ in the regulation of HPA axis activity.

5

The influence of calcium antagonists [verapamil, nifedipine, and MgCl2] on rat gastric damage induced by ethanol in vivo and in vitro

84%

Ostrowski J., Pesta J., Linnik D., Butruk E.

Journal of Physiology and Pharmacology

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1993

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tom 44

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nr 3

6

New spectrophotometric methods for the determination of nifedipine in pharmaceutical formulations

84%

Rahman N., Azmi S. N. H.

Acta Biochimica Polonica

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2005

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tom 52

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nr 4

Two simple, sensitive and economical spectrophotometric methods were developed for the determination of nifedipine in pharmaceutical formulations. Method A is based on the reaction of the nitro group of the drug with potassium hydroxide in dimethyl sulphoxide (DMSO) medium to form a coloured product, which absorbs maximally at 430 nm. Method B uses oxidation of the drug with ammonium molybdate and subsequently reduced molybdenum blue is measured at 830 nm. Beer's law is obeyed in the concentration range of 5.0-50.0 and 2.5-45.0 µg ml-1 with methods A and B, respectively. Both methods have been successfully applied for the assay of the drug in pharmaceutical formulations. No interference was observed from common pharmaceutical adjuvants. The reliability and the performance of the proposed methods are established by point and interval hypothesis tests and through recovery studies.

7

Effects of calcium channel antagonists on the reinforcing properties of morphine, ethanol and cocaine as measured by place conditioning

67%

Biala G., Langwinski R.

Journal of Physiology and Pharmacology

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1996

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tom 47

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nr 3

8

Nifedipine inhibits the hypoxia-induced decrease in plasma renin activity in conscious dogs

67%

Hohne C., Arntz E., Krebs M. O., Boemke W., Kaczmarczyk G.

Journal of Physiology and Pharmacology

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2003

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tom 54

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nr 2

Acute hypoxia induces a decrease in plasma renin activity (PRA), mediated, e.g., by an increase in adenosine concentration, calcium channel activity, or inhibition of ATP-sensitive potassium channels. The decrease in PRA results in a decrease in angiotensin II (AngII) and plasma aldosterone concentration (PAC). This study investigates whether these hypoxia-induced mechanisms can be inhibited by the L-type voltage-dependent calcium channel antagonist nifedipine. Eight conscious, chronically tracheotomized dogs received a low sodium diet (0.5 mmol Na·kg body wt-1·day-1). The dogs were studied twice in randomized order, either with nifedipine infusion (1.5 µg·kg body wt-1·min-1, Nifedipine) or without (Control). The dogs were breathing spontaneously: first hour, normoxia [inspiratory oxygen fraction (FiO2)=0.21]; second and third hour hypoxia (FiO2=0.1). In Controls, PRA (6.8±0.8 vs. 3.0±0.5 ngAngI·ml-1·min-1), AngII (13.3±1.9 vs. 7.3±1.9 pg/ml), and PAC (316±50 vs. 69±12 pg/ml) decreased during hypoxia (P<0.05). In Nifedipine experiments, PRA (6.5±0.9 vs. 10.5±2.4 ngAngI·ml-1·min-1) and AngII (14±1.1 vs. 18±3.9 pg/ml) increased during hypoxia, whereas the decrease in PAC (292±81 vs. 153±41 pg/ml) was blunted (P<0.05). These results foster the idea that the hypoxia-induced decrease in PRA involves L-type calcium channel activity.

9

The role of calcium in the regulation of melatonin biosynthesis in the retina

59%

Zawilska J. B.

Acta Neurobiologiae Experimentalis

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1992

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tom 52

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nr 4

Ograniczanie wyników

Inhibition of potassium-induced ciliary reversal in Fabrea salina by inorganic and organic calcium channel blockers

Influence of nifedypine on the hyperalgesic action of duodenal distention in sheep

Calcium channel blockers impair the pituitary-adrenocortical responses to central adrenergic receptors stimulation

Nitric oxide in the adrenergic- and CRH-induced activation of hypothalamic-pituitary-adrenal axis

The influence of calcium antagonists [verapamil, nifedipine, and MgCl2] on rat gastric damage induced by ethanol in vivo and in vitro

New spectrophotometric methods for the determination of nifedipine in pharmaceutical formulations

Effects of calcium channel antagonists on the reinforcing properties of morphine, ethanol and cocaine as measured by place conditioning

Nifedipine inhibits the hypoxia-induced decrease in plasma renin activity in conscious dogs

The role of calcium in the regulation of melatonin biosynthesis in the retina