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EFFECTS OF ATRIAL NATRIURETIC PEPTIDE ON AORTIC BARORECEPTOR ACTIVITY IN RATS

MA XIU-YING, ZHANG WAN-YU , HE RUI-RONG

(Departmentt of Phystology, Institute of Basic Medicine, Hebei Medical College, Shijiazhang 050017)

Abstract

Effects of atriopeptin ff (AP ff)on the aortic baroreceptor activity in rats were studied in the isolated aorta arch-aortic nerve preparation in situ. By perfusing the isolated aortic arch with AP 1 (2. 0 }tg/ml) in rats，at constant intra-aortic pressure (IAP)of 13. 3 kPa，the integral of aortic nerve activity (IANA) was increased by 64士27%(p<0. 001)，the stepwise increases and decreases of IAP were correspondingly accompanied by increase and decrease in IANA，while the saturation pressure (SP) and the operating range (OR) of aortic baroreceptor activity were decreased from 22. 5士0.5 to 21. 3士0. 5 kPa (P<0. 05) and 12. 1士0. 4 to 10. 6士0. 4 (P<0. 05)，respective1y，and the threshold pressure (TP) did not show any changes. The function curve of
aortic baroreceptor was shifted to left and upward，and the peak integral value (PIV) and the peak slope (PS) of the curve were increased from 508士66 to 730士52%(P<0. 05)，55.6士7.5to93.2士6.80o·kPa-1 (P<0. 05)，respectively: After washing out of AP 11(，the IANA returned to the control level. By perfusing the aortic arch with sodium nitroprusside (NP，1: 0 4g/ml)，at constant intra-aortic pressure (IAP) of 13. 3 kPa，although the IANA was decreased as compared with the control，there was no statistical significance， (P>O. 05).There were no changes in TP，SP and OR during stepwise increases and decreases of IAP，the function curve of aortic barorecep
for and PS were not affected by NP，but the PIV was decreased from 667士78 to 50-2士72%(P<0. 05).Taken together，the results show that the aortic baroreceptor activity was facilitated by AP 11，an effect which was not attributed to its vasodilating action. It is proposed that the effect of AP )Q on aortic baroreceptor may result from its direct action on the ANP receptors within the area of aortic baroreceptor.

Key words: atrial natriuretic peptide;aortic baroreceptor，integral of aortic nerve activity;saturation pressure ;

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Citing This Article：

MA XIU-YING, ZHANG WAN-YU , HE RUI-RONG. EFFECTS OF ATRIAL NATRIURETIC PEPTIDE ON AORTIC BARORECEPTOR ACTIVITY IN RATS. Acta Physiol Sin 1994; 46 (5): (in Chinese with English abstract).