OBJECTIVETo explore the effect of 5-HT2A-receptors coupled with superoxide anion (O2-) on respiratory regulation signal transductionin passageway in the medial area of nucleus retrofacialis (mNRF).

METHODSmNRF island was prepared from medullary slices of neonatal SD rats according to Johnson's method and transferred separately into 24-well culture plates with reagents according to protocol, followed by incubation for 60 min at 37 degrees C in a humidified incubator with 5% CO2. Absorbance of 100 microl supernatant was measured by spectrophotometry at 550 nm and the effect of 5-HT and 2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI, agonist of 5-HT2A-receptors) on O2- generation in the mNRF was observed, along with the inhibition of this effect by ketanserin (antagonist of 5-HT2A-receptors) and alpha-lipoic acid (alpha-LA, a antioxidant).

RESULTS5-HT concentration-response curve demonstrated that absorbance peak occurred at 1 micromol/L without further increment with higher concentration. DOI concentration-response curve showed the absorbance peak at 20 micromol/L without further increment. 5-HT and DOI significantly increased the absorbance with comparable effects. Ketanserin and alpha-LA significantly decreased the absorbance generated by 5-HT and DOI.

CONCLUSIONActivation of 5-HT2A receptors results in obvious O2- production in mNRF, suggesting that 5-HT2A receptors regulate respiratory function in association with O2-.