Insomnia: Acupuncture Modulates α7-nAChR Sleep Circuits
Kristen Sparrow • January 10, 2026
My book actually discussed the α7-nAChR receptor and why it is important. It’s a receptor that explains how different tissues act and react with the vagus nerve. These receptors are nerves, but also mast cells. Insomnia is helped by increased vagal activity, and in this animal study they showed the brain reaction. They used commonly used acupuncture points PC6, and ST36 for 5 days.
Objective: To investigate the role of α7-nicotinic acetylcholine receptor (α7-nAChR) in the regulation of neuronal activity and expression of synapse-related proteins in the thalamic reticular nucleus (TRN) of insomnia rats treated by acupuncture.
Methods: A total of 36 male Sprague-Dawley (SD) rats of clean grade were randomly divided into a control group, a model group, an acupuncture group, and an acupuncture+antagonist group, with 9 rats in each group. The model group, the acupuncture group, and the acupuncture+antagonist group were treated with intraperitoneal injection of p-chlorophenylalanine (PCPA) to establish insomnia model. After successful modeling, the acupuncture group and the acupuncture+antagonist group received acupuncture at bilateral Neiguan (PC6) and Zusanli (ST36) once daily for 5 consecutive days. Thirty min before each acupuncture session, the acupuncture+antagonist group was intraperitoneally injected with methyllycaconitine citrate (MLA), an α7-nAChR antagonist, at a dosage of 5 mg/kg while the acupuncture group received the same volume of 0.9% sodium chloride solution. The rats’ daytime spontaneous activity was observed. Neuronal discharge in the TRN was detected using neuroelectrophysiological methods. Immunofluorescence staining was used to detect parvalbumin-positive (PV+) neurons and co-expression of PV+ and postsynaptic density protein-95 (PSD-95) in the TRN.
Results: Compared with the control group, the model group showed increased daytime spontaneous activity (P<0.01); decreased average fluorescence intensity and positive number of PV+ neurons in the TRN (P<0.01); decreased neuronal discharge frequency (P<0.01), prolonged inter-discharge intervals (P<0.01) in the TRN; reduced number of PV+/PSD-95 double-positive cells in the TRN (P<0.01). Compared with the model group, the acupuncture group showed decreased daytime spontaneous activity (P<0.01); increased average fluorescence intensity and positive number of PV+ neurons in the TRN (P<0.01); increased neuronal discharge frequency (P<0.01), shortened inter-discharge intervals (P<0.01) in the TRN; increased number of PV+/PSD-95 double-positive cells in the TRN (P<0.05). Compared with the acupuncture group, the acupuncture+antagonist group exhibited increased daytime spontaneous activity (P<0.01); reduced average fluorescence intensity and positive number of PV⁺ neurons in the TRN (P<0.01); decreased neuronal discharge frequency (P<0.05), prolonged inter-discharge intervals (P<0.05) in the TRN; reduced number of PV+/PSD-95 double-positive cells in the TRN (P<0.01).
Conclusion: α7-nAChR are involved in mediating the regulatory effect of acupuncture on circadian rhythm disturbances in PCPA-induced insomnia rats. Blocking α7-nAChR attenuates the activating effect of acupuncture on TRN neurons, and reduces the expression of PSD-95 protein on GABAergic neurons.
Keywords: GABAergic Neurons; acupuncture; insomnia; postsynaptic density protein-95 (PSD-95); thalamic reticular nucleus (TRN); α7-nicotinic acetylcholine receptor (α7-nAChR).
