Cardiovascular effects of human recombinant interleukin-1 beta in conscious rats.

Cardiovascular effects of human recombinant interleukin-1 beta (hrIL-1 beta) were investigated in normotensive rats using a computerized analysis of arterial blood pressure in conscious, unrestrained animals. Intravenous injection of hrIL-1 beta induced a rapid and short-lasting rise in blood pressure associated with a first slight tachycardia followed by a second sustained and pronounced increase in heart rate. These effects occurred in a dose-related manner. Pretreatment with a converting-enzyme inhibitor (perindopril) did not modify the hrIL-1 beta-induced increase in blood pressure. Blockade of beta 1-adrenoceptors (atenolol) prevented the tachycardia, but did not significantly affect the pressor response to hrIL-1 beta. On the contrary, the hrIL-1 beta-induced increase in blood pressure was inhibited by an alpha 1-adrenoceptor antagonist (prazosin), whereas the tachycardia was untouched. Finally, pretreatment with a cyclooxygenase inhibitor (indomethacin) completely abolished the cardiovascular response to hrIL-1 beta. These results suggest that the hrIL-1 beta-induced pressor response and associated tachycardia require the synthesis of prostaglandins and involve a sympathetic nervous system activation but do not depend on the renin-angiotensin system.