Premium
Substance P and enkephalinergic synapses onto neurokinin‐1 receptor‐immunoreactive neurons in the pre‐Bötzinger complex of rats
Author(s) -
Liu YingYing,
WongRiley Margaret T. T.,
Liu JinPing,
Wei XiaoYan,
Jia Yi,
Liu HuiLing,
Fujiyama Fumino,
Ju Gong
Publication year - 2004
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2004.03099.x
Subject(s) - substance p , tachykinin receptor 1 , glutamatergic , colocalization , gabaergic , glutamate receptor , excitatory postsynaptic potential , neuroscience , inhibitory postsynaptic potential , enkephalin , neuroligin , neurotransmitter , neuropeptide , glycine receptor , biology , chemistry , glycine , receptor , biochemistry , central nervous system , amino acid , opioid
Our previous studies have demonstrated that neurokinin‐1 receptor (NK1R)‐immunoreactive (ir) neurons in the pre‐Bötzinger Complex (pre‐BötC), the hypothesized kernel of respiratory rhythmogenesis, receive both glutamatergic excitatory and GABAergic or glycinergic inhibitory inputs. Neuromodulators, such as substance P (SP) and opioids, play important roles in normal respiratory activity and respiratory disorders. The identification of the relationship between neurotransmitters and NK1R‐ir neurons at the cellular level is essential for understanding the synaptic interaction within the pre‐BötC network. Using immunofluorescence and immunogold‐silver staining, we wished to exploit SP and enkephalin (ENK) immunoreactivity and their relationships with glutamate, GABA, glycine, or NK1R in the pre‐BötC in adult Sprague–Dawley rats. The pre‐BötC contained a substantial amount of SP‐ir and ENK‐ir boutons. They were largely colocalized with glutamate and much less so with GABA. Glycine immunoreactivity was rarely found in either SP‐ir or ENK‐ir boutons. A number of SP‐ir boutons were ENK‐ir as well. Synapses were commonly found between SP‐ir or ENK‐ir terminals and NK1R‐ir neurons in the pre‐BötC. Most of them were asymmetric. Symmetric synapses made up 10% of all synapses examined between SP‐ir boutons and NK1R‐ir neurons, and 19% of ENK/NK1R synapses. Colocalization of SP and/or ENK with glutamate in boutons in the pre‐BötC implies the combined synaptic release of excitatory amino acid and neuropeptides, which may exert combined post‐synaptic effects onto NK1R‐ir neurons and contribute to respiratory activity.