Expression of alpha-7 nAChRs on spinal cord-brainstem neurons controlling inspiratory drive to the diaphragm.
In the present study, we determined whether alpha-7 subunit containing nicotinic acetylcholine receptors (nAChRs) are expressed by neurons within the pre-Botzinger complex (pre-BotC), bulbospinal, and phrenic motor nuclei in the rat. alpha-7 Immunohistochemistry combined with cholera toxin B (CTB), a retrograde tracer was used to detect expression of alpha-7 nAChRs by phrenic motor and bulbospinal neurons. Neurokinin-1 receptor immunoreactivity was used as a marker for pre-BotC neurons. Of the CTB-positive neurons in the phrenic nuclei, 60% exhibited immunoreactivity for alpha-7 nAChRs. Of the bulbospinal neurons in the paramedian reticular nuclei (PMn), gigantocellular nuclei (Gi), raphe nuclei, rostral ventrolateral medulla (RVLM) and nucleus tractus solitarius, 20-50% were found to express alpha-7 nAChR immunoreactivity. Of the peudorabies virus (PRV) labeled bulbospinal neurons in PMn, Gi, raphe and RVLM, 9-12% co-expressed alpha-7 nAChRs. Immunoreactivity for alpha-7 nAChRs was also detected in 57% of the neurokinin-1 receptor containing neurons presumed to reside in pre-BotC. These findings suggest that nicotinic cholinergic regulation of the chest wall pumping muscles may occur at multiple levels of the central nervous system.
Dehkordi
Ozra
O
Department of Surgery, Howard University Hospital, Washington, DC 20060, USA. odehkordi@howard.edu
Haxhiu
Musa A
MA
Millis
Richard M
RM
Dennis
Gary C
GC
Kc
Prabha
P
Jafri
Anjum
A
Khajavi
Mehran
M
Trouth
C Ovid
CO
Zaidi
Syed I
SI
D000818:Animals; D001933:Brain Stem / Q000166:cytology / Q000378:metabolism*; D003964:Diaphragm / Q000502:physiology*; D007150:Immunohistochemistry; D001239:Inhalation / Q000502:physiology*; D008297:Male; D009046:Motor Neurons / Q000378:metabolism*; D010791:Phrenic Nerve / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D011978:Receptors, Nicotinic / Q000378:metabolism*; D012132:Respiratory Muscles / Q000502:physiology; D012137:Respiratory System / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D014018:Tissue Distribution; D064569:alpha7 Nicotinic Acetylcholine Receptor
C579165:Chrna7 protein, rat; D018040:Receptors, Neurokinin-1; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor