Abstract: Objective To evaluate time curves of the expression of natriuretic peptide receptor A(NPR-A) and C(NPR-C) in the area of nucleus of the solitary tract after myocardial ischemia(MI) in the rat, and to investigate its relation with the cholinergic neurons and the catecholamine neurons. Methods All adult male SD rats were divided randomly into blank control group, sham group and myocardial ischemia(MI) group. After reproduction of the MI model, the rats were sacrificed on day 3, day 7, day 14, day 18 and on day 28 later, and the expressions of NPR-A and NPR-C in the area of nucleus of the solitary tract were detected respectively by Western blotting method, and the double labeling of NPR-A, NPR-C with ChAT, TH in the nucleus of the solitary tract was investigated with immunofluorescence method. Result The expression quantity of NPR-A in the area of nucleus of the solitary tract of the rat was significantly decreased(P<0.05) on day 14, and then increased, until the day 28 later the expression quantity of NPR-A was significantly increased than blank control group(P<0.01). While the expression of NPR-C was marked decreased than blank control group on day 3, day 7, day 14 and day 18(P<0.01). The immunofluorescence staining detection in the nucleus of the solitary tract indicated that there were many double labeling neurons of NPR-C/TH, but there was a little double labeling neurons of NPR-A /TH, and there has no double labeling neuron of NPR-A, NPR-C with ChAT. Conclusions The regulating action of the natriuretic pepitde on cardiovascular function in the nucleus of the solitary tract was enhanced, and this effect could not be depended directly on the influence with the cholinergic neurons and the catecholamine neurons.

Key words: Key words: myocardial ischemia, natriuretic peptide receptor, the nucleus of solitary tract, Western blotting, immunofluorescence chemistry staining, Rat