The Enhancing of Nicotinic Receptor operated intracellular calcium Mobilization by calcitoning - gene -related peptide ( CGRP ) At single Skeletal Muscle cells

Calcitiomine - Gene - Related Peptide ( CGRP ) and single skeletal Muscle cells .The main aim of this thesis was to sllIdy the role of CGRP in the regulation of neuromuscular transmission through its effect on nAChR-operated Ca2+ . mobilization induced by ACh in single mouse flexor digitorum braves (FDB) muscle cells and to elucidate the possible mechanism(s) by which CGRPPinduces this effect. It was also intended to compare results obtained from FDBmuscle cells with those reported from experiments using the nerve-stimulated mouse diaphrag111 preparations. In addition, the last part of this thesis was alsoplanned to explore the influence of diabetes mellitus induced experimentally in mi~e on the effect of ACh and CGRP on the intracellular Ca2+ ([Ca2+]i) mobilization. The ~ Ca2’ Ii level in the present study was measured in single musc1f~ cells isolated from the FDB muscle on either normal untreated mice ormice in which diabetes mellillls was induced experimentally by streptozotocin (STZ) injection. The muscle cells were loaded with the Ca2+ indicator fluo-3/AMand were imaged using the confocal laser scanning microscope. The results were stored, analyzed and normalized against the basal Ca2+ levels using INSIGHT-To achieve the goal of this thesis different sets of experiments were carried out. The effect .of ACh (0.1-3 ~l1no\lL) on the [Ca2+]j mobilization in single muscle cells of normal mice was investigated. The bath-application of ACh to the celJ suspension generated a biphasic elevation (fast and slow components) in (Ca2+]j at the single muscle cell endplate region. The peak amplitudes of both fast and’ slow components in these two-phasic [Ca2+h elevations were AChhconcentration-dependent.