harmacological studies have demonstrated that
polysaccharide-peptide (PSP), a novelbiological response modifier extracted
from Coriolus versicolor, has a potent immunoregulatoryactivity. Recently, many experiments indicate that there exist some regulatory netwoks betwn immune system and nervous system. The effects of PSP on the electrical activities of mediobasal hypothalamic (MBH) neurons and on the immune functions of splenic lymphocytes of rats wereinvestigated in the present experiment in order to clarify the relationship of the immunoregulatoryeffect of PSP with the nervous system.The MBH neurons recorded in the present experiment were identified histologically and located onthe both sides of the 3rd ventrical in area of arcuate nucleus. It was found that in the experimentalgroupafter administration of PSP (1000mg/kg/day, po) for 5 consecutive days, the averagespontaneous discharge frequency of MBH neurons was 4.69±0.27Hz (n=62), while in the controlgroup it was only 1.79±0.12Hz (n=81). The difference was very significant (P<0.001),indicating that PSP could activate the MBH neurons and increase their discharge frequency.In the experimental group the number of acidic α-naphthal aceti esterase (ANAE) -positivecells for T lymphocytes accounts for 55.1±9.7% (n=10). It was significantly higher than that incontrol group (41.0±9.4%, n=10), which indicated that PSP could enhance the immune functionof splenic T lymphocytes. There was no significant change in the percentage of membrane surfaceimmunoglobulin G (SmIgG) -positive cells for B lymphocytes after PSP treatment (48.3±10. 8% inPSP group vs 56.5±7.7% in control group, P>0.05).EIectroacupuncture perfomed at the acupoints "Zusanli" and "Sanyinjiao" in the control groupresulted in an inhibitory response (decrease in discharge frequency) in 67% of MBH neurons (16/24). PSP could increase the percentage of inhibitory response to 92% of MBH neurons (35/38). Itsuggests that acupuncture could have a negtive feedback regulatory effect on the enhancement ofimmune function by PSP.