Neurotrophin-dependent plasticity of neurotransmitter segregation in the rat superior cervical ganglion in vivo
Por:
Vega A., Cancino-Rodezno A., Valle-Leija P., Sánchez-Tafolla B.M., Elinos D., Cifuentes F., Morales M.A.
Publicada:
1 ago 2016
Resumen:
Neurons are able to segregate transmitters to different axon endings.
Segregation is a plastic neuronal feature; it can be modulated by
synaptic environment. We have demonstrated that neurotrophin and other
cellular factors regulate segregation in sympathetic neurons in culture.
Herein we tested the hypothesis that sympathetic neurons in vivo are
also capable to exhibit neurotrophin-dependent plasticity of
segregation. To explore the effect of neurotrophin on segregation, we
reduced ganglionic NGF content by the transection of postganglionic
nerves (axotomy) of the superior cervical ganglia. By
immunohistochemistry, Western blot, and PCR analyses, we explored the
effect of axotomy on the NGF and BDNF content of ganglionic neurons, and
on the segregation extent of vesicular acetylcholine transporter (VAChT)
and methionine enkephalin (mENK) in pre-ganglionic varicosities. We
analyzed NGF-dependence of the changes found by applying exogenous NGF.
Axotomy reduced ganglionic NGF and BDNF content, increased NGF
transcripts, and increased VAChT-mENK segregation. Axotomy also
increased the number of VAChT immunopositive varicosities, and caused
the appearance of a population of VAChT-, mENK- or SV2-containing
varicosities lacking Synaptophysin (Syn). Administration of NGF
prevented changes in NGF content, kept NGF transcripts increased, and
counteracted changes in segregation and in the number of cholinergic
varicosities. The exogenous NGF did not preclude change in BDNF content
or in the occurrence of the VAChT- or mENK-containing varicosities
lacking Syn. Data demonstrate that segregation of transmitters in vivo
is plastic and it is modulated by environmental signals like NGF. We
propose a possible functional correlate of segregation plasticity in the
sympathetic ganglia. (c) 2015 Wiley Periodicals, Inc. Develop Neurobiol
76: 832-846, 2016
Filiaciones:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Biol Celular & Fisiol, 3Er Circuito Exterior S Numero,Cd Univ, Mexico City 04510, DF, Mexico
Departamento de Biología Celular & Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México. 3er Circuito Exterior s/Número, Cd. Universitaria, México, D.F, 04510, Mexico
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