Increase in peripheral blood flow due to extraocular direct irradiation of visible light in rats

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 279; no. 3; pp. H1141 - H1146
• Main Authors: Kobayashi, Keisuke, Kobayashi, Yoshiko, Hashida-Okumura, Akiko, Iimori, Sonoe, Nagai, Katsuya, Nakashima, Hisao
• Format: Journal Article
• Language: English
• Published: United States 01.09.2000
• Subjects: Animals; Blood Flow Velocity - drug effects; Blood Flow Velocity - radiation effects; Dose-Response Relationship, Drug; Enzyme Inhibitors - administration & dosage; Eye Protective Devices; Injections, Intraperitoneal; Laser-Doppler Flowmetry; Lasers; Light; Male; NG-Nitroarginine Methyl Ester - administration & dosage; Nitric Oxide Synthase - antagonists & inhibitors; Nitroprusside; omega-N-Methylarginine - administration & dosage; Oxadiazoles - administration & dosage; Penicillamine - administration & dosage; Penicillamine - analogs & derivatives; Quinoxalines - administration & dosage; Rats; Rats, Wistar; Regional Blood Flow - drug effects; Regional Blood Flow - radiation effects; Skin - blood supply; Skin - radiation effects; Tail; Vasodilator Agents - administration & dosage
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.2000.279.3.H1141

1  The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047; 2  Suginami Clinic, Aioi, Hyogo 678-0051; and 3  Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan We have conducted experiments to clarify the existence of extraretinal photosensitivity in mammals through the measurements of skin blood flow variation due to light irradiation. We found that blood flow shows a synchronized transient increase with a irradiation-nonirradiation sequence. The action spectrum of the phenomenon was found to show peaks at ~410-420 nm, 540-550 nm, and 570- 580 nm. These peaks coincide with the specific optical absorption peaks of B and Q ( , ) bands in sixfold coordinated ferruos-heme complexes such as nitric oxide (NO)-Hb. The blood flow increase in the irradiated duration disappears when the rats are intraperitoneally injected with 1H-[1,2,3]oxydiazolo[4,3-a] quinoxalin-1-one (ODQ), which is an inhibitor of guanylate cyclase, and N G -monomethyl- L -arginine acetate and N G -nitro- L -arginine methyl ester, which are inhibitors of NO synthase. On the basis of the present results, we propose a photochemical model of the photosensitivity mechanism where optical absorption of the sixfold coordinated ferrous heme-NO complex plays a main role. extraretinal photosensitivity in mammals; blood flow increase; photochemical process; nitric oxide-hemoglobin; nitric oxide synthase inhibitor; guanylate cyclase inhibitor