Dopaminergic modulation of axon collaterals interconnecting spiny neurons of the rat striatum
Por:
Guzmán J.N., Hernández A., Galarraga E., Tapia D., Laville A., Vergara R., Aceves J., Bargas J.
Publicada:
1 ene 2003
Resumen:
Dopamine is a critical modulator of striatal function; its absence produces Parkinson's disease. Most cellular actions of dopamine are still unknown. This work describes the presynaptic actions of dopaminergic receptor agonists on GABAergic transmission between neostriatal projection neurons. Axon collaterals interconnect projection neurons, the main axons of which project to other basal ganglia nuclei. Most if not all of these projecting axons pass through the globus pallidus. Thus, we lesioned the intrinsic neurons of the globus pallidus and stimulated neostriatal efferent axons antidromically with a bipolar electrode located in this nucleus. This maneuver revealed a bicuculline-sensitive synaptic current while recording in spiny cells. D 1 receptor agonists facilitated whereas D2 receptor agonists depressed this synaptic current. In contrast, a bicuculline-sensitive synaptic current evoked by field stimulation inside the neostriatum was not consistently modulated, in agreement with previous studies. The data are discussed in light of the most recent experimental and modeling results. The conclusion was that inhibition of spiny cells by axon collaterals of other spiny cells is quantitatively important; however, to be functionally important, this inhibition might be conditioned to the synchronized firing of spiny neurons. Finally, dopamine exerts a potentially important role regulating the extent of lateral inhibition.
Filiaciones:
Guzmán J.N.:
Instituto de Fisiologia Celular, Univ. Nacional Autonoma de Mexico, Mexico City DF 04510, Mexico
Hernández A.:
Departamento de Fisiología, Ctro. de Invest./de Estud. Avanzados, Mexico City DF 07000, Mexico
Galarraga E.:
Instituto de Fisiologia Celular, Univ. Nacional Autonoma de Mexico, Mexico City DF 04510, Mexico
Tapia D.:
Instituto de Fisiologia Celular, Univ. Nacional Autonoma de Mexico, Mexico City DF 04510, Mexico
Laville A.:
Instituto de Fisiologia Celular, Univ. Nacional Autonoma de Mexico, Mexico City DF 04510, Mexico
Vergara R.:
Instituto de Fisiologia Celular, Univ. Nacional Autonoma de Mexico, Mexico City DF 04510, Mexico
Aceves J.:
Departamento de Fisiología, Ctro. de Invest./de Estud. Avanzados, Mexico City DF 07000, Mexico
Bargas J.:
Instituto de Fisiologia Celular, Univ. Nacional Autonoma de Mexico, Mexico City DF 04510, Mexico
Instituto de Fisiologia Celular, Univ. Nacional Autonoma de Mexico, Circuito exterior s/n, Mexico City DF 04510, Mexico
All Open Access, Bronze
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