Different effects of electroacupuncture on esophageal motility and serum hormones in cats with esophagitis

We aim to investigate the effects of different electroacupuncture (EA) frequencies at ST-36 on esophageal motility, and to compare the effect of EA on serum gastrin (GAS), motilin (MTL), and vasoactive intestinal peptide (VIP). Thirty-two cats were divided into four equal groups. All animals underwent a Heller myotomy. After esophagitis developed two frequencies (2/15 Hz or 2/100 Hz) of EA were delivered into ST-36 (LEA group [low EA], HEA group [high EA]). Animals submitted to EA on a non-point region (EANP) were used as controls (LEANP group, HEANP group), respectively. Esophageal motility was continuously monitored. The lower esophageal sphincter pressure (LESP) decreased significantly after myotomy. The LESP decreased in both LEA and LEANP cats, and in LEA cats the pressure decrease was greater. The LESP increased in the HEA group, which was higher than that in the HEANP group (P < 0.05). High-frequency EA significantly increased the peak amplitude in esophageal peristalsis. There was a decrease in serum GAS and MTL in LEA cats compared with LEANP cats (both P < 0.01). GAS and MTL were higher in the HEA group than in the HEANP group (both P < 0.01). Serum VIP decreased in the HEA group (P < 0.05), while it increased in the LEA group (P < 0.05), compared with EANP groups, respectively. EA with a high frequency at ST-36 enhances LESP as well as esophageal motility, while EA with a low frequency decreases LESP. The effect of EA is acupoint-specific, and this effect appears to be mediated through GAS, MTL and VIP.