Vasodilator Effects of Ibudilast on Retinal Blood Vessels in Anesthetized Rats

• Published in: Biological & Pharmaceutical Bullein Vol. 32; no. 11; pp. 1924 - 1927
• Main Authors: Noguchi, Masahiro, Mori, Asami, Sakamoto, Kenji, Nakahara, Tsutomu, Ishii, Kunio
• Format: Journal Article
• Language: English; Japanese
• Published: Japan The Pharmaceutical Society of Japan 01.11.2009; Pharmaceutical Society of Japan; Japan Science and Technology Agency
• Subjects: Anesthesia; Animals; cyclooxygenase; ibudilast; Male; prostanoid; Pyridines - pharmacology; Rats; Rats, Wistar; retinal blood vessel; Retinal Vessels - drug effects; Vasodilator Agents - pharmacology
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.32.1924

Ibudilast (3-isobutyryl-2-isopropylpyrazolo[1,5-α]pyridine) is clinically used as a cerebral vasodilator in Japan. However, the effects of ibudilast on retinal blood vessels have not been fully examined. The aim of this study, therefore, was to examine the effects of ibudilast on retinal blood vessels in rats in vivo. Male Wistar rats (8 to 10 weeks old) were anesthetized with thiobutabarbital (120 mg/kg, intraperitoneally (i.p.)). Retinal vascular images were captured with a fundus camera system for small animals, and the diameter of retinal blood vessels was measured. Ibudilast (0.1 and 1 mg/kg, intravenously (i.v.)) elicited a sustained increase in the diameter of retinal blood vessels and heart rate without altering systemic blood pressure. The effects of ibudilast were significantly reduced by treatment with the nonselective cyclooxygenase inhibitor indomethacin (5 mg/kg, i.p.). These results suggest that ibudilast dilates retinal blood vessels through cyclooxygenase-dependent mechanisms in rats in vivo.