title: Adrenoceptor-Mediated Post- and Pre-Synaptic Regulations of the Reticulospinal Neurons in Rat Caudal Pontine Reticular Nucleus.
abstract: The central noradrenergic system participates in diverse nervous functions. Nevertheless, our knowledge of the action of adrenoceptors in motor regulation is still lacking. Intriguingly, reticulospinal neurons in the caudal pontine reticular nucleus (PnC) receive fairly dense noradrenergic innervation and play an important role in motor control. Here, after demonstrating the expression of α1- and α2-adrenoceptors in the PnC, we found that noradrenaline elicited a post-synaptic effect (inward or outward whole-cell current at -70 mV holding) on PnC reticulospinal neurons. The α1- and α2-adrenoceptors were co-expressed in individual PnC reticulospinal neurons to mediate an inward and an outward current component at -70 mV holding, respectively, which, when superposed, produced the overall post-synaptic effects of noradrenaline (NA). More importantly, the activation of post-synaptic α1- or α2-adrenoceptors indeed exerted opposing modulations (excitation vs. inhibition) on the firing activities of individual PnC reticulospinal neurons. Furthermore, the activation and inhibition of the Na+-permeable non-selective cationic conductance (NSCC) were demonstrated to be coupled to α1- and α2-adrenoceptors, respectively. Additionally, the activation of α2-adrenoceptors activated K+conductance. Pre-synaptically, the α2-adrenoceptors were expressed to attenuate the miniature excitatory postsynaptic current (mEPSC) in PnC reticulospinal neurons, but not to affect the miniature inhibitory postsynaptic current (mIPSC). Consistently, the evoked EPSC in PnC reticulospinal neurons was suppressed after the activation of pre-synaptic α2-adrenoceptors. Thus, the excitatory input and post-synaptic dynamics of PnC reticulospinal neurons are indeed intricately modulated by the activation of α1- and α2-adrenoceptors, through which motor control may be regulated in an adaptive manner by the central noradrenergic system.
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors.forename: Nian
authors.initials: N
authors.lastname: Yang
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors.forename: Qi-Cheng
authors.initials: QC
authors.lastname: Qiao
authors.affiliation: Student Brigade, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors.forename: Yu-Hui
authors.initials: YH
authors.lastname: Liu
authors.affiliation: Department of Neurobiology, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors.forename: Ji-Qiang
authors.initials: JQ
authors.lastname: Zhang
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing, 400038, People's Republic of China. zhianhu@aliyun.com.
authors.forename: Zhi-An
authors.initials: ZA
authors.lastname: Hu
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing, 400038, People's Republic of China. zhangjun.cc@gmail.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001933:Brain Stem / Q000378:metabolism*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D015640:Ion Channel Gating / Q000187:drug effects; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D011941:Receptors, Adrenergic / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*
chemical_list: D011941:Receptors, Adrenergic; D012964:Sodium; D009638:Norepinephrine
keywords: Adrenoceptors; Caudal pontine reticular nucleus; Motor control; NSCC; Noradrenaline; Reticulospinal neurons