The beta subunits of voltage-dependent calcium channels are known to modify calcium channel currents through pore-forming alpha1 subunits. Of the four beta subunits reported to date, the beta3 subunit is highly expressed in smooth muscle cells and is thought to consist of L-type calcium channels. To determine the role of the beta3 subunit in the voltage-dependent calcium channels of the cardiov...

The GABAB-mediated modulation of spinal neurons in the lamprey is investigated in this study. Activation of GABAB receptors reduces calcium currents through both low- (LVA) and high-voltage activated (HVA) calcium channels, which subsequently results in the reduction of the calcium-dependent potassium (KCa) current. This in turn will reduce the peak amplitude of the afterhyperpolarization (AHP)...

Mice were rendered tolerant and dependent to morphine by subcutaneous injection of morphine over a period of 5 days. The effects of acute and chronic administration of dihydropyridine calcium channel antagonist nifedipine on the development of tolerance and naloxone-precipitated morphine withdrawal signs were investigated. A single injection of nifedipine proved to be effective in inhibiti...

Small arteries exhibit tone, a partially contracted state that is an important determinant of blood pressure. In arterial smooth muscle cells, intracellular calcium paradoxically controls both contraction and relaxation. The mechanisms by which calcium can differentially regulate diverse physiological responses within a single cell remain unresolved. Calcium-dependent relaxation is mediated by ...

Introduction: Our previous studies showed that hydroalcoholic extract of leaf of Vitis vinifera relaxes the phenylephrine-induced contraction in rat thoracic aorta. This effect was dependent on endothelial integrity and NO-cGMP system. The vasorelaxant effect of extract was much lesser on KCl-induced contraction. We, therefore, postulated that K+ channels are involved. The main aim of the pr...

conclusions ip injection of cb1 receptor antagonist might have an anxiogenic profile in rat, whereas calcium channel blocker attenuated the anxiogenic effect of am251. our results suggest that there is an interaction between functions of l-type ca2+ channels and cannabinoid system in anxiety. background the elevated plus-maze (epm) has been broadly used to investigate anxiolytic and anxiogenic ...

Decreased leptin-induced endothelium-dependent vasodilation has been reported in spontaneously hypertensive rats (SHR). Here, we report leptin-induced vasoconstriction in endothelium-denuded pulmonary artery and thoracic aorta from SHR and sought to characterize calcium handling underlying these mechanisms. Vasoreactivity to leptin was evaluated on pulmonary artery and thoracic aorta rings from...

This article evaluates the effect of membrane active channel-forming polyene antibiotic (PA) of levorin and its alkyl derivatives on the muscle performance. The membrane channels of muscle cells are capable to transport ions of potassium, sodium, and calcium. In the period of an intensive muscle exercise, the necessity for organic substrates increases and these channels start to work with the g...

OBJECTIVE To examine the hypothesis that hydrogen sulfide (H2S) regulates the colonic motility by modulating both L-type voltage-dependent calcium channels and large conductance Ca2+-activated K+ (BKCa) channels. METHODS Immunohistochemistry was performed on rat colonic samples to investigate the localization of the H2S-producing enzymes cystathionine-β-synthase (CBS) and cystathionine-γ-lyas...

The mechanisms of toxicity of cadmium (Cd(2+)) in adrenal steroidogenesis were investigated in vitro in adrenocortical cells of rainbow trout (Oncorhynchus mykiss). Toxicity of Cd(2+) was increased in absence of extracellular Ca(2+), but was prevented in Ca(2+)-supplemented medium. Pretreatment of cells with BAY K8644 (BAY), an agonist of voltage-dependent calcium channels, increased the Cd(2+)...