TRH regulates action potential shape in cerebral cortex pyramidal neurons
Por:
Rodríguez-Molina V., Patino, J, Vargas Y., Sánchez-Jaramillo E., Joseph-Bravo P., Charli, JL
Publicada:
7 jul 2014
Resumen:
Thyrotropin releasing hormone (TRH) is a neuropeptide with a wide neural distribution and a variety of functions. It modulates neuronal electrophysiological properties, including resting membrane potential, as well as excitatory postsynaptic potential and spike frequencies. We explored, with whole-cell patch clamp, TRH effect on action potential shape in pyramidal neurons of the sensorimotor cortex. TRH reduced spike and after hyperpolarization amplitudes, and increased spike half-width. The effect varied with dose, time and cortical layer. In layer V, 0.5 µM of TRH induced a small increase in spike half-width, while 1 and 5 µM induced a strong but transient change in spike half-width, and amplitude; after hyperpolarization amplitude was modified at 5 µM of TRH. Cortical layers III and VI neurons responded intensely to 0.5 µM TRH; layer II neurons response was small. The effect of 1 µM TRH on action potential shape in layer V neurons was blocked by G-protein inhibition. Inhibition of the activity of the TRH-degrading enzyme pyroglutamyl peptidase II (PPII) reproduced the effect of TRH, with enhanced spike half-width. Many cortical PPII mRNA+ cells were VGLUT1 mRNA+, and some GAD mRNA+. These data show that TRH regulates action potential shape in pyramidal cortical neurons, and are consistent with the hypothesis that PPII controls its action in this region. © 2014 Elsevier B.V.
Filiaciones:
Rodríguez-Molina V.:
Univ Nacl Autonoma Mexico, Fac Med, Dept Fisiol, Mexico City 04510, DF, Mexico
Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), AP 70250, México, D.F. 04510, Mexico
Facultad de Medicina, Universidad Autónoma Del Estado de Morelos, Cuernavaca, Morelos, Mexico
Vargas Y.:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Genet Desarrollo & Fisiol Mol, Cuernavaca 62210, Morelos, Mexico
Departamento de Genética Del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Ave. Universidad 2001, Chamilpa, Cuernavaca, Morelos 62210, Mexico
Sánchez-Jaramillo E.:
Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría, Ramón de la Fuente Muñíz, México D.F., Mexico
Joseph-Bravo P.:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Genet Desarrollo & Fisiol Mol, Cuernavaca 62210, Morelos, Mexico
Departamento de Genética Del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Ave. Universidad 2001, Chamilpa, Cuernavaca, Morelos 62210, Mexico
Charli, JL:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Genet Desarrollo & Fisiol Mol, Cuernavaca 62210, Morelos, Mexico
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