EFFECT OF ELECTRICAL STIMULATION ON Β-Adrenergic RECEPTOR POPULATION AND CYCLIC AMP PRODUCTION IN CHICKEN AND RAT SKELETAL MUSCLE CELL CULTURES

Abstract

Expression of the beta-adrenergic receptor (betaAR) and its coupling to cyclic AMP (cAMP) synthesis are important components of the signaling system that controls muscle atrophy and hypertrophy, and the goal of this study was to determine if electrical stimulation in a pattern simulating slow muscle contraction would alter the betaAR response in primary cultures of avian and mammalian skeletal muscle cells. Specifically, chicken skeletal muscle cells and rat skeletal muscle cells that had been grown for 7 d in culture were subjected to electrical stimulation for an additional 2 d at a pulse frequency of 0.5 pulses/sec and a pulse duration of 200 msec. In chicken skeletal muscle cells, the betaAR population was not significantly affected by electrical stimulation; however, the ability of these cells to synthesize cyclic AMP was reduced by approximately one-half. In contrast, the betaAR population in rat muscle cells was increased slightly but not significantly by electrical stimulation, and the ability of these cells to synthesize cyclic AMP was increased by almost twofold. The basal levels of intracellular cyclic AMP in neither rat muscle cells nor chicken muscle cells were affected by electrical stimulation.

Activation of histamine H3 receptor decreased cytoplasmic Ca2+ imaging during electrical stimulation in the skeletal myotubes

“…During this process, CGRP increases voltage-gated SR Ca 2 þ release within hours, resulting from a quantitatively similar increase in releasable SR Ca 2 þ content (Avila et al, 2007). When chicken and rat skeletal muscle cells were cultured for 7 days and were then subjected to electrical stimulation for additional 2 days, the ability of these cells to synthesize cAMP was increased by almost two-fold (Young et al, 2000). In our study, electrical stimulation of differentiated C2C12 myotubes may have caused upregulation of cAMP biosynthesis; in this case, H 3 receptor activation may inhibit cAMP elevation and prevent overcontraction.…”

ß2-Agonists and cAMP inhibit protein degradation in isolated chick (Gallus domesticus) skeletal muscle

“…These results support the view that the in vivo hypertrophic effect of clenbuterol and cimaterol on skeletal muscle in both birds and mammals is due, at least in part, to a reduction in protein breakdown, probably mediated by 2 -adrenoceptors. -Adrenoceptors, predominantly of the 2 -subtype, have been identified in quail primary myotubes (Young et al, 2000) and in rat skeletal muscle (Jensen et al, 1995).…”

Electrotherapeutic device/protocol design considerations for visual disease applications

“…The influence of exogenous electrical currents and electric fields, and their influence on various cell plasma membrane receptors, has been well documented [17], [22], [23]. By activating these cell receptors, biochemical events within the cell cytoplasm and nucleoplasm can be influenced through a number of plasma membrane interactions and in different cellular signaling pathways.…”

“…Young et al and Cheng et al reported that endogenous and exogenous electrical stimulation supports production and release of the nucleoside/nucleotide derived family of molecules including adenosine triphosphate (ATP) and cyclic adenosine monophosphate (cyclic AMP); along with promoting protein synthesis, amino acid transport and cellular Ca ++ influx [22], [24]. ATP is known to act as a neurotransmitter in the retina.…”