Search results for "nifedipine"

Berberine Mediated Positive Inotropic Effects on Rat Hearts via a Ca2+-Dependent Mechanism

2020

Previous studies showed that berberine, an alkaloid from Coptis Chinensis Franch, might exert a positive inotropic effect on the heart. However, the underlying mechanisms were unclear. Here, we reported that berberine at 10-20 µM increased the left ventricular (LV) developed pressure and the maximal rate of the pressure rising, and it increased the maximal rate of the pressure descending at 20 µM in Langendorff-perfused isolated rat hearts. These effects diminished with the concentration of berberine increasing to 50 µM. In the concentration range of 50-300 µM, berberine increased the isometric tension of isolated left ventricular muscle (LVM) strips with or without electrical stimulations,…

Effects of nifedipine on renal and cardiovascular responses to neuropeptide y in anesthetized rats

2021

Neuropeptide Y (NPY) acts via multiple receptor subtypes termed Y1, Y2 and Y5. While Y1 receptor-mediated effects, e.g., in the vasculature, are often sensitive to inhibitors of L-type Ca2+ channels such as nifedipine, little is known about the role of such channels in Y5-mediated effects such as diuresis and natriuresis. Therefore, we explored whether nifedipine affects NPY-induced diuresis and natriuresis. After pre-treatment with nifedipine or vehicle, anesthetized rats received infusions or bolus injections of NPY. Infusion NPY (1 µg/kg/min) increased diuresis and natriuresis, and this was attenuated by intraperitoneal injection of nifedipine (3 µg/kg). Concomitant decreases in heart ra…

Treatment of hypertension with a combination of nifedipine and atenolol compared with atenolol alone. Preliminary report.

1988

Cyclosporin- and nifedipine-induced gingival overgrowth in renal transplant patients: correlations with periodontal and pharmacological parameters, a…

1996

The factors associated with cyclosporin A (CsA)- and nifedipine (Nif)-induced gingival overgrowth were investigated in 113 renal transplant recipients receiving CsA alone (Group 1) [n = 61], CsA and Nif (Group 2) [n = 28], or azathioprine (Aza) (Control Group) [n = 24]. Periodontal and pharmacological parameters were assessed for each patient. The patients with a gingival overgrowth index (GOI) score1 were considered responders (R); those with a score/= 1 were non-responders (NR). Gingival overgrowth occurred in 33.7% of the patients in Groups 1 and 2; 60% of the responders were receiving CsA+Nif. In R, no relationship was found between the GOI and the periodontal and pharmacological parame…

Vasopressin receptors involved in adrenergic neurotransmission in the circular muscle of the human vas deferens

1998

We studied the effects of vasopressin on the adrenergic responses of in vitro preparations of circular muscle from the vas deferens obtained from 28 men undergoing elective vasectomy. Vasopressin (3 x 10(-9)-3 x 10(-8) M) enhanced the phasic contractions elicited by electrical field stimulation and noradrenaline. This potentiation was blocked by the vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)vasopressin (10(-6) M) but not by the vasopressin V2 receptor antagonist [d(CH2)5, D-Ile2,Ile4,Arg8]vasopressin (10(-6) M). The Ca2+ antagonist nifedipine (10(-6) M) did not affect the potentiation of electrical field stimulation induced by vasopressin and noradrenaline but reduced KCl-induced con…

Factors Related to the Occurrence of Microalbuminuria During Antihypertensive Treatment in Essential Hypertension

2002

The objective of the study was to assess the factors related to the occurrence of microalbuminuria during the follow-up of a young adult group with essential hypertension that had not been previously treated. Normo-albuminuric essential hypertensives, <50 years old, who had not been previously treated with antihypertensive drugs and who did not have diabetes mellitus were included. After the initial evaluation, patients were treated using only nonpharmacological measures (n=62), β-blockers (n=38), ACE inhibitors (n=64), calcium channel blockers (n=8), and several classes (n=15). Measurements were taken for office blood pressure, biochemical profile, and 24-hour urinary albumin excretion…

Modulation of adrenergic responses of human vas deferens by K+ channel inhibitors.

2010

Objectives The present study was designed to evaluate the role of K + channels in the adrenergic responses of human vas deferens as well as the intervention of dihydropyridine-sensitive Ca 2+ channels on modulation of adrenergic responses by K + channel inhibitors. Methods Ring segments of the epididymal part of the vas deferens were taken from 32 elective vasectomies and mounted in organ baths for isometric recording of tension. We then studied the effects of K + channel blockers on neurogenic and norepinephrine-induced contractile responses. Results Addition of tetraethylammonium (TEA, 10 −3 M), a nonspecific K + channel blocker, or charybdotoxin (10 −7 M), a nonselective inhibitor of lar…

Enhancement by vasopressin of adrenergic responses in human mesenteric arteries.

1997

Vasopressin not only acts directly on blood vessels through V1-receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vitro and in vivo. The aim of the present study was to investigate whether subpressor concentrations of vasopressin could modify the constrictor responses to norepinephrine and electrical stimulation of the perivascular nerves in human mesenteric arteries. Human mesenteric artery rings (3-3.5 mm long, 0.8-1.2 mm OD) were obtained from 38 patients undergoing abdominal operations. The arterial rings were suspended in organ bath chambers for isometric recording of tension. Vasopressin (3 x 10(-11) M) enhanced the contractions elicited…

Influence of nifedipine on the metabolism of gingival fibroblasts.

1994

Calcium antagonists are the gold standard in the therapy of coronary heart disease and hypertension. The prototype of these drugs is nifedipine which, as well as its therapeutic effects on the cells of the cardiovascular system, also has unpleasant side effects on other organ systems. One side effect can be a missive hyperplasia of the gingiva, the reason for which are unclear. In vitro experiments were designed to elucidate the influence of nifedipine on the growth of human gingival fibroblasts in short and long term (72 hours, 6 weeks) cell culture. The following cellular parameters were determined quantitatively: cell proliferation (cell count, [3H]thymidine incorporation), protein synth…

Effect of divalent cations on KCl- and noradrenaline-induced contractile responses in rat aorta after nifedipine treatment.

1999

Abstract Nifedipine (1 μM) relaxed the sustained contractile responses induced by 1 μM noradrenaline or 60 mM KCl in rat aortic strips. After washing, a second addition of the spasmogens gave smaller tonic contractions than the first one. Even more, a third addition of KCl also gave a smaller contraction than the first one, but a complete recovery of the contractile response to noradrenaline was obtained by a third addition of this agonist. Application of cumulative amounts of Ca2+ or Ba2+ (2.4–24 mM) on the residual contraction in response to these agents after nifedipine treatment, but in the absence of the blocker, restored the magnitude of the contractile responses. Addition of cumulati…