Effects on Rats of Low Intensity and Frequency Electromagnetic Field Stimulation on Thoracic Spinal Neurons Receiving Noxious Cardiac and Esophageal Inputs med./bio.

To study the effects of electromagnetic fields on the activity of thoracic spinal neurons responding to noxious visceral stimuli (low intensity and low frequency electromagnetic field stimulation provides substantial pain relief in patients with various chronic pains).

A mixture of algogenic chemicals for noxious cardiac stimulation was administered by catheter. Noxious esophageal distension was produced by water inflation of a latex balloon.

• animal
• rat/Sprague-Dawley
• partial body: chest

After the onset of electromagnetic fields, excitatory neuronal responses to intrapericardial chemicals were reduced in 75% (24/32) spinal neurons, increased in three neurons and were not affected in five neurons. The inhibitory effect on neurons occurred 10-20 min after the onset of the field. Even after termination of electromagnetic field exposure, the suppression of spinal neuronal activity lasted for 1-2 hours.
In contrast, excitatory responses of 39% (7/18) neurons to esophageal distension were inhibited, five were excited and six were not affected by the field.
Data showed that electromagnetic fields generally reduced nociceptive responses of spinal neurons to noxious cardiac chemical stimuli, whereas it was not effective for nociceptive responses to esophageal mechanical stimulation.