Divergent profile between hypothalamic and plasmatic aminopeptidase activities in WKY and SHR. Influence of beta-adrenergic blockade.
Life Sci 2017;
192:9-17. [PMID:
29155297 DOI:
10.1016/j.lfs.2017.11.022]
[Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/06/2017] [Accepted: 11/15/2017] [Indexed: 11/20/2022]
Abstract
AIMS
Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) differ in their renin-angiotensin system function and sympathetic tone. The metabolism of angiotensins and vasopressin depends on the action of certain aminopeptidases whose activity may be influenced by the autonomic nervous system. Their regulation may differ between WKY and SHR in hypothalamus and plasma according to the sympathetic tone. We analyzed aminopeptidases responsible for the hydrolysis of certain angiotensins, vasopressin, cholecystokinin or enkephalins in hypothalamus and plasma of WKY and SHR in untreated controls rats and under beta-adrenoceptor blockade. Systolic blood pressure, food intake, water intake and diuresis were measured as parameters modulated by the autonomic nervous system and the above mentioned peptides.
MAIN METHODS
Glutamyl-, aspartyl-, cystinyl- and alanyl-aminopeptidase activities were analyzed fluorimetrically in plasma and hypothalamus of control and propranolol-treated (100mg/kg/day administered in drinking water for 1month) WKY and SHR, using arylamide derivatives as substrates.
KEY FINDINGS
An opposite response of aminopeptidases to propranolol treatment between plasma and hypothalamus was observed in either WKY and SHR. Furthermore, the behavior of aminopeptidases was inversed between WKY and SHR either in hypothalamus and plasma: while the activity increased in hypothalamus and decreased in plasma of WKY, it decreased in hypothalamus and increased in plasma of SHR.
SIGNIFICANCE
These results revealed an inverse response of aminopeptidases between hypothalamus and plasma and also an opposite behavior of these enzymes between WKY and SHR in hypothalamus and plasma. These observations support the involvement of the sympathetic system in the modulation of aminopeptidase activities.
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