Effect of captopril on intracellular free calcium ([Ca2+]i) of thymocytes in spontaneously hypertensive rats.
Hypertension is associated with dysfunction of the immune system. Intracellular free calcium ([Ca2+]i) was reportedly increased in immune cells, such as lymphocytes and thymocytes, both in hypertensive patients and in animals. To evaluate if captopril has an effect on the immune system, [Ca2+]i in thymocytes was monitored during the development of hypertension from 4-24 weeks, and after treatment with captopril for 4 and 12 weeks in spontaneously hypertensive rats (SHR). SHR (n = 24) were treated with captopril at a dose of 20 mg/kg/day at 12 weeks of age after establishment of hypertension. Untreated SHR (n = 17) and normotensive Wistar Kyoto (WKY n = 14) served as control. [Ca2+]i of thymocytes was measured using Fura-2. It was found that [Ca2+]i of thymocytes decreased both in SHR and WKY from 4-12 weeks of age. From 12-24 weeks, [Ca2+]i in thymocytes remained at a constant level in WKY. However, [Ca2+]i in thymocytes increased significantly in SHR after 12 weeks. Captopril (CAP) treatment significantly lowered [Ca2+]i in thymocytes derived from SHR at 24 weeks. This treatment was associated with a moderate reduction in systolic blood pressure. Established hypertension in SHR is associated with increased [Ca2+]i in thymocytes. This may be indicative of immunological dysfunction. Captopril inhibits the increase in [Ca2+]i of thymocytes in SHR.
Xie
L
L
First Affiliated Hospital of Fujian Medical College, Fuzhou, PR China.
Chen
D
D
Wu
D
D
Wang
H
H
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002216:Captopril / Q000494:pharmacology*; D006973:Hypertension / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D002216:Captopril; D002118:Calcium