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)

Equine precision cut lung slices (PCLS) were used to evaluate the ability of several pharmacologic compounds, parasympatholytics atropine, ipratropium, tiotropium and phosphodiesterase (PDE) 4-inhibitor cilomilast, to inhibit methacholine (MCh) induced bronchial constriction. The study war performed using vital lung samples from 20 horses, harvested immediately after euthanasia and lung examination.Tissue samples from the cranial, caudal and accessory lobe were taken for histological examination. Viability in PCLS of 250 +/- 20 microm was confirmed by observation of cilia movement and bronchial contraction in response to the addition of increasing concentrations of MCh (10(-8) to 10(-4) mol/l). Washing in pure RPMI-medium resulted in bronchial reopening. After incubation (20 minutes in an RPMI-solution containing cilomilast (10(-5) mol/l), atropine, ipratropium or tiotropium (10(-7) mol/l) each group (randomized, placebo controlled) was treated with MCh again. After reopening the unaffected viability of the PCLS was confirmed by the addition of MCh. EC50 values were calculated from bronchial cross-sections for each contraction. EC50 values significantly increased after atropine, ipratropium and tiotropium addition. No difference was found for cilomilast and in control slices. Statistical analysis showed a large interindividual, but a small intraindivual variability. No correlation was found between the clinical examination, histological findings and PCLS' responsiveness. We were able to confirm Vietmeier's (2007) values for the responsiveness of equine PCLS to MCh and to proof the effect of several new bronchodilatators using a new technique that allows the assessment of several substances in the same horse.
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PMID:Pharmacological studies of bronchial constriction inhibited by parasympatholytics and cilomilast using equine precision-cut lung slices. 2049 30

Trout pineal photoreceptor cells were dissociated by trypsin-DNase digestion and further purified by a Percoll gradient centrifugation. Total cells or purified photoreceptor cells were then embedded in a collagen gel, or layered on culture-treated polycarbonate membranes, or maintained in suspension, with RPMI 1640 medium or BGjb medium. It has been shown that cells maintain a rhythmic production of melatonin for at least seven 24 h light/dark cycles under these conditions. In this complementary study, the morphofunctional state of the photoreceptor cells was examined 1) by electron (transmission, scanning) microscopy, and 2) by pharmacological tests under different lighting conditions. Using polycarbonate membranes together with RPMI 1640 medium appeared the most suitable. The segmented organization of photoreceptor cells was well preserved when using the culture-treated membranes. It tended to disappear in cells embedded in the collagen gel and was lost after passage through the Percoll gradient. However, this one allowed obtention of an homogeneous population of photoreceptors, as recognized by their intracellular components. Intracellular organelles were rather well preserved in the embedded photoreceptors. The study also provides novel information on the nature of second messengers involved in the photoperiodic control of melatonin production in photoreceptor cells. From the effects of an adenylyl cyclase activator and a phosphodiesterase inhibitor it appeared that 1) total cells and Percoll-selected cells behaved similarly, 2) the nocturnal rise in melatonin secretion was associated with an increase in cAMP content, and 3) a fall in cAMP may be a mechanism through which light reduces melatonin secretion by photoreceptor cells. Cyclic GMP, the metabolism of which also appeared to be controlled by light, did not seem involved in the photoperiodic control of melatonin production. The method proposed herein offers interesting perspectives for the study of the photoneuroendocrine properties of isolated photoreceptor cells.
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PMID:Pineal photoreceptor cells in culture: fine structure, and light/ dark control of cyclic nucleotide levels and melatonin secretion. 2155 50


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