Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The phosphodiesterase inhibitor UK 61260 exhibits positive inotropic activity in animal studies and is under clinical investigation for treatment of congestive heart failure (CHF). We examined the lusitropic and inotropic responses to UK 61260 in electrically driven (1 Hz, 37 degrees C) human auricular trabeculae (AUT, aortocoronary bypass operation, nonfailing hearts, n = 13) and in papillary muscle strips (PAP) from moderately (New York Heart Association, NYHA II-III, mitral valve replacement, n = 6) and terminally (NYHA IV, heart transplantation, n = 7) failing human hearts. For comparison, we studied the effects of UK 61260 after prestimulation with forskolin (FOR 0.03 microM) and isoprenaline (ISO 0.03 microM), as well as the effects of milrinone (MIL 1-1,000 microM), ISO (0.01-10 microM), ouabain (OUA, 0.1 microM), and Ca2+ (1.8-15 mM) in failing human myocardium alone. UK 61260 increased force of contraction (FOC), peak rate of tension increase (+T) and decay (-T) significantly (p less than 0.01) in AUT but not in PAP of NYHA II-III and NYHA IV. Only after prestimulation (FOR and ISO), was UK 61260 effective in stimulating FOC in NYHA II-III and NYHA IV. UK 61260 increased (p less than 0.01) +T and -T, resulting in a shortening of twitch time. As judged from the EC50 values, UK 61260 increased FOC more potently than MIL. The effectiveness of OUA and Ca2+ in increasing developed tension in human failing myocardium was significantly higher as compared with UK 61260. We conclude that during stimulation of the cardiac beta-adrenoceptor-adenylate-cyclase system, UK 61260 increases myocardial systolic and diastolic function in failing human myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of the phosphodiesterase inhibitor UK 61260 on human myocardial inotropy and diastolic relaxation. 137 20

Cardiac Ca2+ current (ICa) was shown to be regulated by cGMP in a number of different species. Recently, we found that the NO-donor SIN-1 (3-morpholino-sydnonimine) exerts a dual regulation of ICa in frog ventricular myocytes via an accumulation of cGMP. To examine whether NO also regulates Ca2+ channels in human heart, we investigated the effects of SIN-1 on ICa in isolated human atrial myocytes. An extracellular application of SIN-1 produced a profound stimulatory effect on basal ICa at concentrations > 1 pM. Indeed, 10 pM SIN-1 induced a approximately 35% increase in ICa. The stimulatory effect of SIN-1 was maximal at 1 nM (approximately 2-fold increase in ICa) and was comparable with the effect of a saturating concentration (1 microM) of isoprenaline, a beta-adrenergic agonist. Increasing the concentration of SIN-1 to 1-100 microM reduced the stimulatory effect in two thirds of the cells. The stimulatory effect of SIN-1 was not mimicked by SIN-1C, the cleavage product of SIN-1 produced after liberation of NO. This suggests that NO mediates the effects of SIN-1 on ICa. Because, in frog heart, the stimulatory effect of SIN-1 on ICa was found to be due to cGMP-induced inhibition of cGMP-inhibited phosphodiesterase (cGI-PDE), we compared the effects of SIN-1 and milrinone, a cGI-PDE selective inhibitor, on ICa in human. Milrinone (10 microM) induced a strong stimulation of ICa (approximately 150%), demonstrating that cGI-PDE controls the amplitude of basal ICa in this tissue. In the presence of milrinone, SIN-1 (0.1-1 nM) had no stimulatory effect on ICa, suggesting that the effects of SIN-1 and MIL were not additive. We conclude that NO may stimulate ICa in human atrial myocytes via inhibition of the cGI-PDE.
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PMID:Nitric oxide regulates the calcium current in isolated human atrial myocytes. 786 Jul 25