Subarachnoid bupivacaine increases human cerebrospinal fluid concentration of serotonin.
OBJECTIVE
Serotonin (5-hydroxytryptamine [5-HT]) has antinociceptive properties at the spinal level. Activation of descending serotonergic neurons or topically applied 5-HT at the spinal cord inhibits rostral spread of sensory information. Epidural anesthesia has been shown to increase 5-HT in plasma, and local anesthetics may interfere with 5-HT reuptake and metabolism. For these reasons, the action of subarachnoid local anesthetics on cerebrospinal fluid (CSF) 5-HT concentrations has been studied.


METHODS
Six volunteers received lumbar spinal anesthesia with 0.5% bupivacaine through subarachnoid catheters, and CSF and plasma 5-HT concentrations were determined radioenzymatically before and after anesthesia.


RESULTS
Plasma 5-HT was unchanged, but CSF 5-HT increased by 300% after bupivacaine administration (P < .02).


CONCLUSIONS
Subarachnoid bupivacaine increases local 5-HT concentration. This may have implications for nociceptive gating as well as for local vasoregulation.
Department of Anesthesia, Frederiksberg Hospital, Denmark.
O
O
Naesh
I
I
Hindberg
C
C
Christiansen
D000328:Adult; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage*; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D012701:Serotonin / Q000097:blood / Q000134:cerebrospinal fluid*; D013346:Subarachnoid Space
D000779:Anesthetics, Local; D012701:Serotonin; D002045:Bupivacaine