Orexins excite neurons of the rat cerebellar nucleus interpositus via orexin 2 receptors in vitro.
Orexins are newfound hypothalamic neuropeptides implicated in the regulation of feeding behavior, sleep-wakefulness cycle, nociception, addiction, emotions, as well as narcolepsy. However, little is known about roles of orexins in motor control. Therefore, the present study was designed to investigate the effect of orexins on neuronal activity in the cerebellum, an important subcortical center for motor control. In this study, perfusing slices with orexin A (100 nM-1 microM) or orexin B (100 nM-1 microM) both produced neurons in the rat cerebellar interpositus nucleus (IN) a concentration-dependent excitatory response (96/143, 67.1%). Furthermore, both of the excitations induced by orexin A and B were not blocked by the low-Ca(2+)/high-Mg(2+) medium (n = 8), supporting a direct postsynaptic action of the peptides. Highly selective orexin 1 receptor antagonist SB-334867 did not block the excitatory response of cerebellar IN neurons to orexins (n = 22), but [Ala(11), D-Leu(15)] orexin B, a highly selective orexin 2 receptor (OX(2)R) agonist, mimicked the excitatory effect of orexins on the cerebellar neurons (n = 18). These results demonstrate that orexins excite the cerebellar IN neurons through OX(2)R and suggest that the central orexinergic nervous system may actively participate in motor control through its modulation on one of the final outputs of the spinocerebellum.
Yu
Lei
L
Department of Biological Science and Technology and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.
Zhang
Xiao-Yang
XY
Zhang
Jun
J
Zhu
Jing-Ning
JN
Wang
Jian-Jun
JJ
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001583:Benzoxazoles; D002529:Cerebellar Nuclei / Q000166:cytology / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism* / Q000494:pharmacology; D009287:Naphthyridines; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism* / Q000494:pharmacology; D064446:Orexin Receptors; D000068797:Orexins; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000378:metabolism*; D018013:Receptors, Neuropeptide / Q000819:agonists / Q000378:metabolism*; D014508:Urea / Q000031:analogs & derivatives
C420062:1-(2-methylbenzoxazol-6-yl)-3-(1,5)naphthyridin-4-yl urea; D001583:Benzoxazoles; D047908:Intracellular Signaling Peptides and Proteins; D009287:Naphthyridines; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D010455:Peptides; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide; D014508:Urea