PURPOSE To develop a method of using isolated rat retina as a biosensor in experiments on controlled drug release for measuring the resultant concentration of free model drug in living tissue and for testing the biocompatibility of the polymers and polymeric nanostructures used as drug carriers. METHODS The method is based on the monotonic dependence of the photoresponse kinetics of retinal r...

BACKGROUND Resveratrol is a cardioprotective agent with known antiarrhythmic effects that has recently been shown to inhibit phosphodiesterase (PDE) enzyme activity. Thus, it is possible that resveratrol increases the inotropic effect of sympathomimetic agents, as PDE inhibitors do but, unlike other PDE inhibitors, its effect may not be accompanied by proarrhythmia due to its antiarrhythmic act...

It has been difficult to separate/identify the roles of ClC-2 and CFTR in Cl(-) transport studies. Using pharmacological agents, we aimed to differentiate functionally between ClC-2 and CFTR Cl(-) channel currents. Effects of CFTR inhibitor 172 (CFTRinh172), N-(4-methylphenylsulfonyl)-N'-(4-trifluoromethylphenyl)urea (DASU-02), and methadone were examined by whole cell patch clamp on Cl(-) curr...

It is currently believed that a nonselective cation (NSC) channel, which responds to arginine vasotocin (an antidiuretic hormone) and stretch, regulates Na+ absorption in the distal nephron. However, the mechanisms of regulation of this channel remain incompletely characterized. To study the mechanisms of regulation of this channel, we used renal epithelial cells (A6) cultured on permeable supp...

The large conductance voltage- and Ca(2+)-activated K(+) (BK) channel is a major regulator of detrusor smooth muscle (DSM) excitability and contractility. Recently, we showed that nonselective phosphodiesterase (PDE) inhibition reduces guinea pig DSM excitability and contractility by increasing BK channel activity. Here, we investigated how DSM excitability and contractility changes upon select...

OBJECTIVE: To investigate the influence of thyroid hormone on steroid production and cAMP accumulation in porcine theca (Tc) and granulosa cells (Gc) isolated from preovulatory follicles as well as in luteal cells isolated during the mid-developing luteal phase. METHODS: Granulosa and theca cells separated from pig ovarian follicles and pieces of corpora lutea were cultured in the incubation me...

Aiming to improve the developmental competence of bovine oocytes during meiotic block, this study evaluated the effects of a serum replacer (Knockout SR®) and hormones (gonadotropins and estradiol) supplementation of prematuration medium (TCM119 with 0.5 mM IBMX [IBMX group] or 25 μM roscovitine [ROSC group]) on the kinetics of oocyte nuclear maturation and embryo development. Most IBMX and ROS...

The aim of our study was to examine the influence of 3-isobutyl-1-methyl-xanthine (IBMX), inhibitor of cAMP and cGMP phosphodiesterases on the reproductive efficiency of gonadotropin-stimulated rabbits. Ovarian cycle and ovulation of control rabbits were induced by PMSG followed by hCG administration. Experimental animals received PMSG and hCG together with IBMX (at dose 5 or 25 mg/animal). Aft...

Previous studies have shown that disruption of cyclic nucleotide metabolism by phosphodiesterase inhibitors and cyclic nucleotide analogues damages photoreceptors in rod-enriched retinae. In these studies the cone photoreceptors appeared damaged only after the surrounding rods had begun to degenerate. Our aim was to test if cone photoreceptors were susceptible to similar treatments in the absen...

Secretion of intrinsic factor (IF) has previously been demonstrated in isolated rabbit fundic mucosa maintained in organ culture. We have now investigated the possibility that cyclic nucleotides may play a role in IF secretion. A phosphodiesterase inhibitor, 3-isobutyl methylxanthine (IBMX), stimulated IF secretion nearly fourfold while increasing tissue levels of both cyclic AMP (cAMP) and cyc...