title: Cyclooxygenase-pathway participates in the regulation of regional cerebral blood flow in response to neuronal activation under normo- and hypercapnia.
abstract: The present study was designed to investigate whether cyclooxygenase products are involved in the regulation of the regional cerebral blood flow, evoked by somatosensory activation (evoked rCBF) under normo- and hypercapnia. Indomethacin (IMC) was used as cyclooxygenase inhibitor. It was applied intravenously (i.v., 10 mg/kg/h) in two experimental protocols-before hypercapnia (i) and after hypercapnia (ii). Somatosensory activation was induced by electrical hind paw stimulation (5 Hz frequency, 5 s duration, 1.5 mA). The evoked rCBF-response was measured in alpha -chloralose anesthetized rats using laser-Doppler flowmetry. IMC abolished completely the effect of hypercapnia on the baseline level of CBF. The drug reduced significantly evoked rCBF-response also. The inhibitory effect of IMC on evoked rCBF-response is better expressed under normocapnia (approximately 70%) than that under hypercapnia (approximately 40%). After IMC application, the normalized evoked rCBF curves peaked earlier as compared to that before its application (P<0.05), although the rise time of 0.5 s was nearly constant regardless of stimulus frequency. In conclusion, the results suggest a participation of IMC-sensitive and cyclooxygenase-dependent mechanisms in the regulation of evoked rCBF, induced by somatosensory stimulation.
authors.affiliation: Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels, Senshu-Kubota-Machi, Akita, Japan. r.bakalova-zheleva@aist.go.jp
authors.forename: R A
authors.initials: RA
authors.lastname: Bakalova
authors.forename: T
authors.initials: T
authors.lastname: Matsuura
authors.forename: I
authors.initials: I
authors.lastname: Kanno
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000378:metabolism; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D006935:Hypercapnia / Q000201:enzymology* / Q000503:physiopathology*; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000502:physiology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow
chemical_list: D016861:Cyclooxygenase Inhibitors; D002245:Carbon Dioxide; D011451:Prostaglandin-Endoperoxide Synthases; D007213:Indomethacin