Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Khellin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed1976

Studies on amikhellin. II.-Inhibition of dna-polymerase from murine sarcoma leukemia virus.

We have previously reported that amikhellin binds to double-stranded DNA by an intercalation process (1). We now report that this drug inhibits the DNA-polymerase from murine sarcoma leukemia virus. The extent of inhibition was found to vary with the nature of the primer-template used : maximum with poly(rA)n-oligo(dT)10 (nucleotide ratio 20:1), minimum with poly(rA)n-poly(dT)n and intermediate with native calf thymus DNA. Experiments performed with synthetic templates of the (rA)-(dT) type have led to the following conclusions as to the mechanism of inhibition: 1) Amikhellin acts at an early stage of the synthesis reaction because the drug is no longer inhibitory when a limited extension of the oligo(dT) primers has been allowed to occur. However, mere incubation of the enzyme with the template in the absence of dTTP is not sufficient to confer resistance to the drug. 2) Progression of enzyme molecules actively engaged in polymerization is stopped when they reach downstream duplex regions to which amikhellin is bound.

DNA↗
PubMed1999

Effects of visnagin on cyclic nucleotide phosphodiesterases and their role in its inhibitory effects on vascular smooth muscle contraction.

1. Visnagin relaxed aortae previously contracted by noradrenaline. This effect was unalterated by endothelium removal and potentiated, at high concentrations, by the previous incubation with sodium nitroprusside. 2. Visnagin weakly inhibited the hydrolytic activity of the cyclic nucleotide phosphodiesterase (PDE) isozymes (PDE5, PDE4, PDE3, cyclic GMP activated PDE2 and PDE1). 3. The present results indicate an involvement of PDE inhibition in the relaxant effect of visnagin at high concentration (>5x10(-5) M).

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2000

Cardiovascular effects of visnagin on rats.

The present article describes the effects of visnagin on systolic blood pressure and heart rate in the anaesthetized rat. Intravenous administration of visnagin (0.3-5 mg kg-1) produced dose-related decreases in blood pressure with no significative changes in heart rate. Under nitric oxide synthase inhibition (L-NAME, 50 mg kg-1) the hypotensive effects of visnagin (5 mg kg-1) were not affected. Visnagin (5 x 10(-6) M-10(-4) M) produced a weak decrease in the rate and amplitude of spontaneous contractions in right atria. Visnagin also caused a weak decrease in peak contractile force and the df/dtmax with no significant changes in the time to peak tension or the time for total contraction in left atria driven at a basal rate of 1 Hz. Visnagin (10(-5) M, 5 x 10(-5) M and 10(-4) M) concentration-dependently decreased pressor response to KCl (IC50 = 5.1 +/- 2.5 x 10(-5) M) and noradrenaline (IC50 = 2.6 +/- 0.9 x 10(-5) M) in rat isolated mesenteric beds. Visnagin (3 x 10(-7) M-10(-4) M) induced a concentration-dependent relaxation of isolated mesenteric arteries contracted by noradrenaline (IC50 = 1.7 +/- 0.8 x 10(-5) M). The relaxant effects in the absence of functional endothelium were not significantly different (IC50 = 1.5 +/- 0.3 x 10(-5) M, P > 0.05) from those observed in segments with intact endothelium. In conclusion, the main mechanism responsible for the acute hypotensive effect of visnagin is the vasorelaxant response induced by this drug in resistance arteries.

Animals↗