Dk. Song et al., CENTRAL GABA(A) AND GABA(B) RECEPTOR MODULATION OF BASAL AND STRESS-INDUCED PLASMA INTERLEUKIN-6 LEVELS IN MICE, The Journal of pharmacology and experimental therapeutics, 287(1), 1998, pp. 144-149
To investigate the modulatory roles of central gamma-aminobutyric acid
(GABA), and GABA, receptors in the regulation of basal and stress-ind
uced plasma interleukin-6 (IL-6) levels, we examined the effects of i.
c.v. injection of GABA receptor agonists and antagonists on basal and
restraint stress-induced plasma IL-6 levels in mice. Muscimol (20-200
ng), a GABA, receptor agonist, and baclofen (5-20 ng), a GABA, recepto
r agonist, injected i.c.v. did not affect the basal levels of plasma I
L-6. In the restraint-stressed animals, muscimol and baclofen inhibite
d the stress-induced plasma IL-6 levels from the dose of 50 and 15 ng,
respectively. Carboxyl)-3-amino-6-(4-methoxyphenyl)-pyridazinium brom
ide (SR-95,531; 0.3-10 ng), a GABA(A) receptor antagonist, and 2-hydro
xysaclofen (1-10 mu g), a GABA, receptor antagonist, injected i.c.v. i
ncreased both the basal and the restraint stress-induced plasma IL-6 l
evels. The i.p. pretreatment of animals with 6-hydroxydopamine (100 mg
/kg) for 3 days significantly inhibited SR-95,531 (3 ng i.c.v.)- but n
ot 2-hydroxysaclofen (10 mu g i.c.v.)-induced increase in the basal pl
asma IL-6 levels. These data suggest that central GABA, and GABA, rece
ptors are involved in the suppressive modulation of basal and restrain
t stress-induced plasma IL-6 levels in mice.