Effects of barbiturates on the inhibitory action of GABA on excitatory response of the stomach to stimulation of vagal afferent fibers in cat

GABAA‐receptor‐mediated inhibition of the delayed increase in intragastric pressure to stimulation of vagal afferent fibres in cats

“…Since GABA dose-dependently inhibited the hexamethonium-resistant delayed increase in intragastric pressure and these effects of GABA were antagonized by bicuculline and picrotoxin, it is probable that this effect of GABA is mediated by the GABA-receptor-ionophore-complex (Okamoto et al, 1987). In this study, low doses of muscimol mimicked the effect of GABA.…”

“…In hexamethonium-treated cats, stimulation of the distal end of the ligated vagal trunk with electrical pulses (1OHz, iSV, 3 ms for lOs) produced a delayed increase in intragastric pressure after the stimulation period, as described previously (Okamoto et al, 1987).…”

“…In the mouse spinal cord, barbiturates enhance bicucullinesensitive GABAA-mediated postsynaptic inhibition (Schulz & Macdonald, 1981;Olsen, 1982). Recently, we found that pentobarbitone enhanced the inhibitory effects of GABA on the delayed contractile response of the stomach (Okamoto et al, 1987).…”

“…The experimental procedures were essentially similar to those of Okamoto et al (1986) and Tsubomura et al (1987). Twenty-five cats of either sex, weighing 2.5 to 4.0kg, were used.…”

“…These inhibitory effects of GABA were antagonized by both picrotoxin and bicuculline. Thus, it was likely that the effects of GABA were mediated by the GABA-receptor-ionophore complex (Okamoto et al, 1987).…”