| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Effects of intracerebroventricular (i. c. v.) administration of peptides on cardiovascular function and renal sympathetic nerve activity (RSNA) were examined in conscious rats.
1)Angiotensin II (AII) elicited an increase in arterial blood pressure (AP) and decreases in heart rate (HR) and RSNA. The inhibitory response of RSNA persisted in sinoaorticdenervated (SAD) rats. Natriuretic response induced by i. c. v. AII was greatly attenuated after bilateral renal denervation. Since activation of RSNA increases tubular sodium absorption, the finding suggests that central AII has facilitatory effect on renal sodium excretion through the RSNA. Water intake induced by All was enhanced in SAD rats, compared to that in intact rats, suggesting involvement of baroreceptors in control of drinking behaviour.
2)Atrial natriuretic polypeptide (ANP) had no significant effects on resting AP, HR, RSNA and renal blood flow. Prior administration of ANP however, attenuated AII-induced pressor response. HR and RSNA responses induced by AII were not affected by the ANP.
3)Endothelin-3 (ET-3) elicited an increase in AP and decreases in HR and RSNA. ET-3 sometimes produced a barrel rotation with a latency of 10-15 min. At the time, prominent and long-lasting increases in HR and RSNA occurred.
4)Interleukin I (IL-1), a cytokine essentially produced by macrophage, has central actions such as fever and ACTH release. Effects of IL-1 on autonomic nervous system, which may play a critical role in the interaction between the immune system and the central nervous system, has not well elucidated. IL-1 increased AP, HR and RSNA followed by an increase in body temperature. The responses were completely abolished by indomethacin. IL-1 also increased plasm noradrenaline and ACTH concentrations.
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