Aim To identify the serotonin(5-HT)subtype receptor mediated 5-HT-induced depolarization in guinea pig celiac ganglion(CG) neurons.Methods Intracellular recordings were made from the isolated guinea pig CG neurons.Results Cyproheptadine(5-HT_(1/2)antagonist) and BRL 24924(5-HT_(1P) receptor antagonist) reversibly inhibited 5-HT-induced slow depolarization.Whereas,spiperone(5-HT_(1A)receptor antagonist) and mianserin(5-HT_2 receptor antagonist) could not inhibit 5-HT-induced slow depolarization.MDL 72222(5-HT_3 receptor antagonist) could not inhibit 5-HT-induced slow depolarization,but it could reversibly inhibit 5-HT-induced fast depolarization.Pressure ejection of MCPP(5-HT_(1P) receptor agonist) on 5-HT sensitive neurons could induce a slow depolarization which could be inhibited by BRL 24924.Conclusion 5-HT-induced fast and slow depolarization is mediated by 5-HT_3 and 5-HT_(1P) receptor,respectively.

Inflammation and lung function decline are the main pathophysiological features of chronic obstructive pulmonary disease (COPD). Acupuncture can improve lung function in patients with COPD, but the underlying mechanisms are not well understood. Orexins (OXs), which are found in peripheral plasma, are neuropeptides that regulate respiration and their levels are related to COPD. Therefore, we hypothesized that acupuncture might alter OXs, reduce lung inflammation and improve lung function in COPD.