Objective: Does carbachol (CCh) require NO/cGMP for inhibition of L-type calcium current (I ) when either adenylyl cyclase Ca(L) activation or phosphodiesterase suppression is used to raise cAMP? Methods: The effects of the NO donor SIN-1 (3-morpholinosydnonimine), CCh and atrial natriuretic peptide (ANP) were evaluated when I had been stimulated by isoproterenol (ISO) or Ca(L) 3-isobutyl-1-met...

RATIONALE Previous studies modulating pharyngeal muscle activity with pharmacologic approaches have targeted membrane receptors on pharyngeal motoneurons. Whether modulation of intracellular pathways can increase pharyngeal muscle activity, however, has not been investigated but is relevant to pharmacologic treatments of obstructive sleep apnea. OBJECTIVES To determine if modulating the secon...

Glucagon (10 nM) caused a transient elevation of intracellular cyclic AMP concentrations, which reached a peak in around 5 min, and slowly returned to basal values in around 30 min. When 1 mM-3-isobutyl-1-methylxanthine (IBMX) was present, this process yielded a Ka of 1 nM for glucagon. The addition of insulin (10 nM) after 5 min exposure to glucagon (10 nM) caused intracellular cyclic AMP conc...

Bovine oocytes cultured in control medium or in medium containing dibutyrylcyclic adenosine monophosphate (dbcAMP) or an inhibitor of cyclic nucleotide phosphodiesterase (3-isobutyl-1-methylxanthine, IBMX) undergo germinal vesicle breakdown (GVBD). On the other hand, mouse oocytes remain arrested at the germinal vesicle (GV) stage when dbcAMP or IBMX is present. When 1 bovine GV stage oocyte is...

Competent larvae of the serpulid polychaete, Hydroides elegans (Haswell), were induced to 24 metamorphose by either 10 M 3-isobutyl 1-methylxanthine (IBMX), adult homogenate, or 30 1 1 mM excess K . Treatment with excess K had adverse effects (P , 0.05) on juvenile growth while IBMX and adult homogenate had no detectable effects (P . 0.1). Metamorphosis was triggered using IBMX in subsequent st...

In isolated canine epicardial coronary arteries perfused with Krebs-Henseleit solution at 37 degrees C, DN-9693, a newly synthesized selective cyclic AMP phosphodiesterase inhibitor, induced vasodilation in a dose-related manner. The threshold dose for inducing vasodilation to DN-9693 was very small, but the maximum vasodilation was not great. The order of potency for ED20 (20% dilatation) was ...

Inhaled prostanoids and phosphodiesterase (PDE) inhibitors have been suggested for treatment of severe pulmonary hypertension. In catheterized rabbits with acute pulmonary hypertension induced by continuous infusion of the stable thromboxane analogue U46619, we asked whether sildenafil (PDE1/5/6 inhibitor), motapizone (PDE3 inhibitor) or 8-Methoxymethyl-IBMX (PDE1 inhibitor) synergize with inha...

Renin release from the juxtaglomerular (JG) cell is stimulated by the second messenger cAMP and inhibited by calcium. We previously showed JG cells contain a calcium sensing receptor (CaSR), which, when stimulated, decreases cAMP formation and inhibits renin release. We hypothesize CaSR activation decreases cAMP and renin release, in part, by stimulating a calcium calmodulin-activated phosphodi...