| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Central regulatory mechanisms of sympatho-adrenomedullaryl functions were examined in rats under urethane anesthesia. Results obtained are as follows : Intracerebroventricular (ICV) administration of bombesin elevated plasma levels of both noradrenaline (NA) and adrenaline (Ad), and nerve activities electrically recorded form both the sympathetic and adrenal branches of the splanchinic nerves. On the other hand, prostaglandin (PG) E2 by the same route selectively elevated the plasma level of NA alone, and nerve activity of the sympathetic but not the adrenal branch. 2) The effect of PGE2 to elevate the plasma level of NA was due to its activation of EP3 receptors in the brain. 3) Interleukin 1beta (IL-1beta), a madiator of immune signals, selectively elevated the plasma level of NA but not AD,as observed with PGE2.4) The effects of bombesin and IL-1beta on the plasma levels of NA and Ad were abolished by ICV pretreatment with indomethacin, an inhibitor of PG synthesis. 5) From the results with L-NAME,an inhibitor of nitric oxide (NO) synthetase, and exyhemoglobin, an NO scavenger, NO produced in the brain by IL-1beta probably mediates this cytokine-induced elevtion of plasma level of NA.
From these results, it is suggested that two different types of neuronal cells probbly exist in the brain ; activation of one neuronal cell group ecxites both the sympathetic and adrenomedullarly systems, while activation of the other neuronal cell group selectively excites the sympathetic system alone. Receptors of bombesin are located on the former neuronal cell group, while those of IL-1beta are located on the latter neuronal cell group in the brain. PGs in the brain produced by bombesin and IL-1beta are probably involved in activation of these neuronal cell groups.
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