Peripheral interleukin-6 administration increases extracellular concentrations of serotonin and the evoked release of serotonin in the rat striatum.
Previous studies have indicated that peripheral administration of interleukin-6 (IL-6) increases brain concentrations of tryptophan and 5-hydroxyindoleacetic acid (5-HIAA), the major catabolite of serotonin (5-HT). To determine whether these changes were related to increased synaptic release of 5-HT, we studied the responses to peripheral administration of IL-6 by in vivo microdialysis and in vivo amperometry. Intraperitoneal injection of recombinant IL-6 resulted in an elevation of microdialysate concentrations of 5-HT in the rat striatum. Also, amperometric measurements indicated that i.p. IL-6 enhanced the 5-HT-like signal obtained from the striatum following electrical stimulation of the dorsal raphe nucleus. These results indicate that the increases in brain concentrations of 5-HIAA observed in earlier studies indeed reflect increased synaptic release of 5-HT.
Zhang
J
J
Department of Pharmacology and Therapeutics, Louisiana State University Medical Center, PO Box 33932, Shreveport, LA 71130-3932, USA.
Terreni
L
L
De Simoni MG
Dunn
A J
AJ
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism*; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D005110:Extracellular Space / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D015850:Interleukin-6 / Q000008:administration & dosage*; D008297:Male; D017551:Microdialysis; D011903:Raphe Nuclei / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000008:administration & dosage; D012701:Serotonin / Q000378:metabolism*
D015850:Interleukin-6; D011994:Recombinant Proteins; D012701:Serotonin