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Circumventing leptin resistance for weight control.

Departments of Neuroscience and Physiology, College of Medicine, University of Florida McKnight Brain Institute, Gainesville, FL 32610-0244, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 05/2001; 98(8):4279-81. DOI: 10.1073/pnas.091101498
Source: PubMed
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    ABSTRACT: Electrophysiological studies of isolated smooth muscle cells have revealed a variety of membrane-conductance changes that contribute to depolarization and excitation. These include activation of inward Cl− and nonselective cation currents, and the suppression of several types of outward K+ currents, leading to depolarization and opening of voltage-dependent Ca2+ current. In most cases, several of these mechanisms operate together in the same cell. We now recognize that [Ca2+]u plays a critical role not only in initiating contraction but in regulating membrane-channel activity. Cl− current is Ca2+ activated, and muscarinic nonselective cation current is facilitated by Ca2+. Cl− and nonselective cation channels therefore participate in a positive feedback loop, where elevation of [Ca2+]; by entry across the membrane or by release from internal stores initiates or promotes depolarization, which in turn leads to further influx of Ca2+ through voltage-dependent Ca2+ channels. These features of excitation of smooth muscle differ from established views, where depolarization is the primary event causing Ca2+ entry and contraction.
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    Arquivos Brasileiros de Endocrinologia & Metabologia 08/2003; 47(4):398-409. · 0.88 Impact Factor

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