Electropuncture influences on learning, memory, and neuropeptide expression in a rat model of vascular dementia**

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Abstract

BACKGROUND:

Studies in recent years have indicated that several neuropeptide-like substances, such as arginine vasopressin (AVP), somatostatin (SS), and β-endorphine (β-EP), are involved in the process of cerebral ischemic damage to cranial nerves.

OBJECTIVE:

To observe the effects of electropuncture on back-shu points, as well as the influence on learning and memory, AVP, SS, and β-EP levels in plasma and brain were measured in a rat model of vascular dementia (VD).

DESIGN:

Randomized controlled trial.

SETTING:

College of Acupuncture and Massage of Guangzhou University of Chinese Medicine.

MATERIALS:

This experiment was performed at the Animal Experiment Center of Guangzhou University of TCM from December 2005 to December 2006. A total of 48 healthy adult male Sprague Dawley rats of SPF-grade, 180–220 g, were provided by The Animal Experiment Center of Guangzhou University of Traditional Chinese Medicine. The following instruments were used: SDQ–30 Dipolar Radio-frequency Electrocoagulator (Shanghai Operation Instrument Factory), Morris Water Maze (The Animal Experiment Center of Guangzhou University of Traditional Chinese Medicine), Type G6805–1 Treating Equipment (Huasheng Equipment Factory, Qingdao, China).

METHODS:

① Eight rats were randomly selected for the control group; the remaining 40 rats underwent 4-vascular occlusion to establish a cerebral ischemia model. Due to the death of 13 rats and 2 hemiplegies during model establishment, there was a total of 25 model rats available for testing. The model rats were divided randomly into 3 groups according to their body weight: electropuncture group (n = 9), medication group (n = 8), and VD group (n = 8). ② Electropuncture group: 25 mm needles (28 gauge) were used to electropuncture (150 Hz, continuous waves, 1.0–2.0 mA, duration of 20 minutes) the following acupoints: Baihui (GV20), Geshu (BL17), Pishu (BL20), and Shenshu (BL23). The acupoints were located according to Experimental acupuncturology and were stimulated electrically by G6805–1 treating equipment. Medication group: Nimotop (certificate number: 110156; 0.6 mg/mL suspension), 20 mL/kg, was perfused once daily intragastrically for 15 days. Model group: the rats were fed once daily with 150 g/L isotonic NaCl for 15 days (20 mL/kg).

MAIN OUTCOME MEASURES:

Morris water maze testing was employed to study learning and memory behavior. Levels of AVP, SS, and β-EP were measured in plasma and brain radioimmunoassay (RIA).

RESULTS:

A total of 33 Sprague Dawley rats were included in the final analysis. In the VD group, AVP and SS levels in plasma and brain were lower than the other groups (P < 0.01). However, β-EP plasma levels decreased significantly (P < 0.01), while β-EP brain levels increased significantly (P < 0.01). The AVP and SS content in plasma and brain, as well as β-EP in plasma, increased (P < 0.01). The levels of β-EP in the brain decreased (P < 0.01). Morris Water maze results demonstrated that the electropuncture, medication, and control groups had shorter escape times than the VD group (P < 0.01). Animals in the electropuncture, medication, and control groups spent more time in the platform quadrant than in the other three quadrants (P < 0.01).

CONCLUSION:

Electropuncture can regulate the amount of AVP, SS, and β-EP in the plasma and brain, and correlates with improved learning and memory in a rat model of VD.

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