HISTOCHEMICAL LOCALIZATION OF NOS ENZYME IN HEART OF MICE AFTER FENOTEROL ADMINISTRATION
Ramesh Kumar, *Pooja Sharma and Sushma Sharma
ABSTRACT
Fenoterol is a short-acting β2 agonist, which also stimulates β1 receptors at doses above the recommended therapeutic doses. It was widely used in New Zealand in the early 1990s but withdrawn from that market because of its association with an excess number of deaths.It is thought that the association of increased risk of death was because it was typically used in excessively large doses for severe acute asthma attacks in the absence of medical assistance. The side effects of fenoterol are typical for b2-adrenoceptor agonists, e.g., hypokalemia, cardiac acceleration, hypotension, and tremor. Histochemistry is a combination of chemistry and histology, in which reactions are carried out on tissue sections or similar preparations and the results examined under a microscope, with the object of combining the advantages of chemical or biochemical specificity and histological localization. Histochemistry is complementary to biochemical analysis of tissue homogenates, since histochemical techniques can give simultaneously biochemical and morphological information. Nitric oxide (NO), first identified as an endothelium-derived relaxation factor, is now recognized to be an intra- and extracellular mediator of cell function. NO produced by the constitutive isoform of nitric oxide synthase (NOS) is a key regulator of homeostasis, whereas the generation of NO by inducible NOS plays an important role in inflammation, host-defense responses, and tissue repair. NO formation is increased during inflammation (rheumatoid arthritis, and ulcerative colitis, Crohn disease), and several classic inflammatory symptoms are reversed by NOS inhibitors. The correlation of structure and biochemical function made possible by histochemical techniques is of unique value in diagnostic and experimental pathology. The present investigation is an attempt to examine short term effects of fenoterol on the major non contractile apparatus which mainly comprises of collagen in left ventricle. The status of antioxidant enzyme nitric oxide synthase has been studied in heart tissue to find out their reserves during fenoterol induced myocardial necrosis. Myonecrosis is a pathophysiological state and during such stage status of antioxidant enzymes is a subject to change.
Keywords: Fenoterol, NOS, Histochemistry, Left ventricle, Paraformaldehyde.
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