Adrenergic receptor-mediated modulation of striatal firing patterns.
Although noradrenaline and adrenaline are some of the most important neurotransmitters in the central nervous system, the effects of noradrenergic/adrenergic modulation on the striatum have not been determined. In order to explore the effects of adrenergic receptor (AR) agonists on the striatal firing patterns, we used optogenetic methods which can induce continuous firings. We employed transgenic rats expressing channelrhodopsin-2 (ChR2) in neurons. The medium spiny neuron showed a slow rising depolarization during the 1-s long optogenetic striatal photostimulation and a residual potential with 8.6-s half-life decay after the photostimulation. As a result of the residual potential, five repetitive 1-sec long photostimulations with 20-s onset intervals cumulatively increased the number of spikes. This 'firing increment', possibly relating to the timing control function of the striatum, was used to evaluate the AR modulation. The β-AR agonist isoproterenol decreased the firing increment between the 1st and 5th stimulation cycles, while the α1-AR agonist phenylephrine enhanced the firing increment. Isoproterenol and adrenaline increased the early phase (0-0.5s of the photostimulation) firing response. This adrenergic modulation was inhibited by the β-antagonist propranolol. Conversely, phenylephrine and noradrenaline reduced the early phase response. β-ARs and α1-ARs work in opposition controlling the striatal firing initiation and the firing increment.
Department of Physiology, National Defense Medical College, Saitama, Japan. Electronic address: ohta@ndmc.ac.jp.
Hiroyuki
H
Ohta
School of Science and Engineering, Tokyo Denki University, Saitama, Japan.
Yu
Y
Kohno
Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Japan; Aeromedical Laboratory, Japan Air Self Defense Force, Tokyo, Japan.
Masashi
M
Arake
Department of Physiology, National Defense Medical College, Saitama, Japan.
Risa
R
Tamura
Teikyo Heisei University, Tokyo, Japan.
Suguru
S
Yukawa
Teikyo Heisei University, Tokyo, Japan.
Yoshiaki
Y
Sato
Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Japan.
Yuji
Y
Morimoto
Department of Physiology, National Defense Medical College, Saitama, Japan.
Yasuhiro
Y
Nishida
Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Japan; Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan.
Hiromu
H
Yawo
D000200:Action Potentials; D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D000075402:Channelrhodopsins; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D004837:Epinephrine / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D008027:Light; D010656:Phenylephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D055647:Rats, Transgenic; D017208:Rats, Wistar; D011941:Receptors, Adrenergic / Q000378:metabolism*
D058646:Adrenergic alpha-1 Receptor Agonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D000075402:Channelrhodopsins; D011941:Receptors, Adrenergic; D010656:Phenylephrine; D011433:Propranolol; D007545:Isoproterenol; D004837:Epinephrine
Alpha1 adrenergic receptor; Beta adrenergic receptor; Noradrenaline; Striatum