TY - JOUR
T1 - Involvement of potassium and calcium channels at the locus coeruleus in fentanyl-induced muscular rigidity in the rat
AU - Lee, Tak Yu
AU - Fu, Miin Jiuan
AU - Lui, Ping Wing
AU - Chan, Samuel H.H.
PY - 1995/10/27
Y1 - 1995/10/27
N2 - Previous work from our laboratory suggested that Goα protein at the locus coeruleus (LC) may be involved in the signal transduction process that underlies muscular rigidity induced by fentanyl. The present study further evaluated the roles of K+ and L-type Ca2+ channels, gating of which is known to be associated with activation of Goa protein, in this process, using Sprague-Dawley rats anesthetized with ketamine. Bilateral microinjection into the LC of tetraethylammonium chloride (100 or 200 pmol), a K+ channel blocker, and S(-)-Bay K 8644 (0.5 nmol), a Ca2+ channel activator, produced significant antagonization of the EMG activation elicited by fentanyl (100 μg/kg, i.v.), as recorded from the sacrococcygeus dorsalis lateralis muscle. On the other hand, local application to the bilateral LC of diazoxide (10 or 20 nmol), an ATP-dependent K+ channel activator, and nifedipine (0.25 or 0.5 pmol), a L-type Ca2+ channel blocker, was ineffective in blunting fentanyl-induced muscular rigidity. These results suggest that activation of K+ channels and/or inhibition of L-type Ca2+ channels secondary to triggering of the Goa protein at the LC may underlie the signal transduction process in the mediation of fentanyl-induced muscular rigidity.
AB - Previous work from our laboratory suggested that Goα protein at the locus coeruleus (LC) may be involved in the signal transduction process that underlies muscular rigidity induced by fentanyl. The present study further evaluated the roles of K+ and L-type Ca2+ channels, gating of which is known to be associated with activation of Goa protein, in this process, using Sprague-Dawley rats anesthetized with ketamine. Bilateral microinjection into the LC of tetraethylammonium chloride (100 or 200 pmol), a K+ channel blocker, and S(-)-Bay K 8644 (0.5 nmol), a Ca2+ channel activator, produced significant antagonization of the EMG activation elicited by fentanyl (100 μg/kg, i.v.), as recorded from the sacrococcygeus dorsalis lateralis muscle. On the other hand, local application to the bilateral LC of diazoxide (10 or 20 nmol), an ATP-dependent K+ channel activator, and nifedipine (0.25 or 0.5 pmol), a L-type Ca2+ channel blocker, was ineffective in blunting fentanyl-induced muscular rigidity. These results suggest that activation of K+ channels and/or inhibition of L-type Ca2+ channels secondary to triggering of the Goa protein at the LC may underlie the signal transduction process in the mediation of fentanyl-induced muscular rigidity.
KW - Electromyogram
KW - Fentanyl
KW - Locus coeruleus
KW - Muscular rigidity
KW - Potassium and L-type calcium channels
KW - Rat
UR - http://www.scopus.com/inward/record.url?scp=0028784155&partnerID=8YFLogxK
U2 - 10.1016/0304-3940(95)12049-A
DO - 10.1016/0304-3940(95)12049-A
M3 - 文章
C2 - 8577396
AN - SCOPUS:0028784155
SN - 0304-3940
VL - 199
SP - 195
EP - 198
JO - Neuroscience Letters
JF - Neuroscience Letters
IS - 3
ER -