Research ReportSeptal stimulation inhibits spinal cord dorsal horn neuronal activity

Deep brain stimulation (DBS) has been used for relieving chronic pain in patients that have been through other existing options. The septum has been one of the targets for such treatment. The purpose of this study was to determine the inhibitory effect of electrical stimulation in the medial septum diagonal band of broca (MSDB) on neuronal activity in the spinal cord of rats anesthetized with sodium pentobarbital. While unilaterally stimulating the MSDB, wide dynamic range neurons in the lumbar region of the spinal cord were recorded in response to graded mechanical stimulation of the hind paws (brush, pressure, and pinch). Stimulation was at 1, 5, 10, and 20 V, at 100 Hz, and 0.1 ms duration. Significant bilateral reduction was observed in response to pressure (ipsilaterally: 0.90 ± 0.05, 0.48 ± 0.06*, 0.55 ± 0.05*, 0.40 ± 0.05*; and contralaterally: 0.70 ± 0.06*, 0.59 ± 0.08*, 0.75 ± 0.05*, 0.49 ± 0.07*) and pinch (ipsilaterally: 0.89 ± 0.08, 0.46 ± 0.05*, 0.54 ± 0.04*, 0.50 ± 0.05*; and contralaterally: 0.78 ± 0.05, 0.61 ± 0.07*, 0.64 ± 0.04*, 0.53 ± 0.06*). Data were expressed as a fraction of control. Significant changes were also found in responses to brush in certain groups (ipsilaterally: 1.08 ± 0.08, 0.72 ± 0.06*, 1.00 ± 0.12, 0.65 ± 0.06*; and contralaterally: 0.93 ± 0.05, 0.77 ± 0.07*, 0.98 ± 0.05, 0.84 ± 0.07). Further analysis suggested that 5 V was adequate for achieving optimal inhibition. It is concluded that the MSDB can be used as alternative target for DBS in the treatment of pain.

Research Highlights►The septum has been one of the targets for deep brain stimulation (DBS) used for relieving chronic pain. ►The inhibitory effect of electrical stimulation of the septum was determined by neuronal activity in the spinal cord. ►Significant bilateral reduction were observed in response to pressure, pinch, and some brush groups. ►Stimulation at 5 V was adequate for achieving optimal inhibition. ►It is concluded that the MSDB can be used as alternative target for DBS in the treatment of pain.