Involvement of G(o) alpha subtype of guanine nucleotide-binding regulatory protein at the locus coeruleus in fentanyl-induced muscular rigidity in the rat.
Previous work from our laboratory suggested that locus coeruleus (LC) and the coerulospinal noradrenergic pathway are intimately related to the elicitation of muscular rigidity by fentanyl. The present study attempted to identify the subtype of guanine nucleotide-binding regulatory protein that may participate in this process, using Sprague-Dawley rats anesthetized with ketamine and under mechanical ventilation. Immunofluorescent staining with a polyclonal antiserum directed against a 39-kDa protein that corresponds to the alpha subunit of G(o) revealed the presence of G(o) alpha immunoreactivity in neurons of the LC. Bilateral microinjection of the same G(o) alpha antiserum into the LC also significantly blunted the enhanced electromyographic activity recorded from the sacrococcygeus dorsalis lateralis muscle induced by intravenous administration of fentanyl (100 micrograms/kg). These results suggest that G(o) alpha protein at the LC may participate in the signal transduction process that underlies muscular rigidity induced by high-dose fentanyl.
Department of Anesthesiology, National Yang-Ming Medical College, Taipei, Taiwan, Republic of China.
M J
MJ
Fu
T C
TC
Lin
P W
PW
Lui
T Y
TY
Lee
S H
SH
Chan
D000818:Animals; D004576:Electromyography / Q000187:drug effects; D005283:Fentanyl; D005455:Fluorescent Antibody Technique; D019204:GTP-Binding Proteins / Q000502:physiology*; D007150:Immunohistochemistry; D008125:Locus Coeruleus / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008845:Microinjections; D009127:Muscle Rigidity / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D009474:Neurons / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012121:Respiration, Artificial; D015398:Signal Transduction / Q000187:drug effects
D019204:GTP-Binding Proteins; D005283:Fentanyl