Objective: To study the effect of electroacupuncture(EA) of "Hegu"(LI 4) and "Sibai"(ST 2) on the electrical activities of stomach-related neurons in the nucleus of solitary tract(NTS) of the rat.Methods: Experiments were performed on 62 Wistar rats anesthetized with mixture solution of urethane((420 mg/kg)) and chloralose((50 mg/kg)

i.p.).The 4

(th)

ventricle of the brain was exposed for inserting glass micropipettes((1 μm) in diameter

10-(30 mΩ) in electrical resistance

and filled with(1 mol) KCl+2% pontamine sky blue)into NTS under the microscopic observation to record electrical activities of neurons.After opening the abdominal cavity and making an incision at the junction between the pylorus and duodenum

a plastic balloon was inserted into the stomach for dilating it.EA(2-(4 V)

(20 Hz) and duration of(2 min)) was applied to the left "Hegu"(LI 4) and "Sibai"(ST 2).If the firing rate of the neuron decreased or increased by 25% or more after EA or gastric dilation stimulation

it was considered to be inhibitory or excitatory reaction.Results: 1) A total of 278 NTS neurons were recorded in the present study.Among them

132 neurons showed apparent excitatory or inhibitory responses to gastric distention via the implanted balloon and were called as stomach-related neurons.Among the 132 neurons

70 were excited

and 62 were inhibited

including 36/62 being inhibited completely.2) Of the 132 stomach-related neurons(17 inhibitory and 24 excitatory neurons)

14/17 and 8/24 presented inhibitory response

and 3/17 and 16/24 excitatory response to EA of "Hegu"(LI 4);while 11/17 and 7/24 presented inhibitory response

6/17 and 17/24 excitatory response to EA of "Sibai"(ST 2) separately

indicating that signals of EA of LI-4and ST-2 and those from gastric dilation could converge to the same NTS neuron.Conclusion: The results indicate that information of EA of "Sibai"(ST 2) and "Hegu"(LI 4) and gastric distention may converge to the same individual NTS neuron.NTS may play an important role in the integration and convergence of the somatic(facial area and LI-4) message and visceral(stomach) message.The present research provides new evidence for the theory of meridian about the specific connection between Hegu Point and the face-mouth region.