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Decrease in cochlear blood flow with infusion of nitric oxide synthase inhibitor and its recovery with L-arginine infusion: comparison with abdominal blood flow and auricular blood flow.
Acta Otolaryngol. 2002 Dec; 122(8):808-15.AO

Abstract

We observed changes in cochlear blood flow (CoBF), abdominal blood flow (AbBF) and auricular blood flow (AuBF) in rats after administration of the nitric oxide (NO) synthase inhibitor N-nitro-L-arginine-methyl ester (L-NAME). Ten min after i.v. infusion of L-NAME, L-arginine, a substrate of NO, was infused (100 mg/kg) intravenously. Using a laser Doppler flowmeter, changes in blood flow were recorded from the basal turn of the right cochlea, abdominal wall or right auricle, and systemic blood pressure (BP) was recorded simultaneously from the left femoral artery. As another parameter of vascular response, vascular conductance (VC) was calculated from blood flow/mean BP. I.v. infusion of L-NAME produced a dose-dependent depression of cochlear VC at concentrations of 0.2 (-18.9%), 1 (-37.9%), 5 (-45.8%) and 10 mg/kg (-48.3%). Infusion of L-arginine partially reversed the decrease of CoBF caused by L-NAME. The group that received a 0.2 mg/kg infusion of L-NAME showed the largest degree of recovery (23.8%) with L-arginine, while the 10 mg/kg group showed the smallest degree of recovery (10.1%). AbBF also decreased after infusion of L-NAME (5 mg/kg) but to a lesser degree (-41.1% depression of VC) and with no significance compared to the decrease in CoBF (5 mg/kg L-NAME). Likewise, AuBF showed a decrease (-44.0% depression of VC) after infusion of L-NAME (10 mg/kg), the decrease being less than that of CoBF (10 mg/kg L-NAME). Recoveries from these decreased levels of VC in the AbBF and AuBF groups appeared to be smaller than those in the CoBF groups at the same dose of L-NAME (5.5% vs 17.3% in abdominal VC; 5.3% vs 10.1% in auricular VC). In a previous study comparing the CoBF changes caused by i.v. infusion and round window application of L-NAME, we proposed that i.v. infusion of L-NAME in rats primarily affects the precapillary arteriole of the spiral modiolar artery, which effectively regulates cochlear microcirculation as a resistance artery. Thus we assume that there may exist an active pathway of the NO/soluble guanylate cyclase/cyclic guanosine monophosphate system in the above vessels. With regard to the finding of a smaller recovery of VC with L-arginine in both the AbBF and AuBF groups, we consider that differences in L-arginine availability or uptake, and in the synthesis of NO, may exist between the cochlear and cutaneous vasculatures.

Authors+Show Affiliations

Department of Otolaryngology, Osaka Medical College, Osaka, Japan.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12542197

Citation

Hoshijima, Hideaki, and Kazuo Makimoto. "Decrease in Cochlear Blood Flow With Infusion of Nitric Oxide Synthase Inhibitor and Its Recovery With L-arginine Infusion: Comparison With Abdominal Blood Flow and Auricular Blood Flow." Acta Oto-laryngologica, vol. 122, no. 8, 2002, pp. 808-15.
Hoshijima H, Makimoto K. Decrease in cochlear blood flow with infusion of nitric oxide synthase inhibitor and its recovery with L-arginine infusion: comparison with abdominal blood flow and auricular blood flow. Acta Otolaryngol. 2002;122(8):808-15.
Hoshijima, H., & Makimoto, K. (2002). Decrease in cochlear blood flow with infusion of nitric oxide synthase inhibitor and its recovery with L-arginine infusion: comparison with abdominal blood flow and auricular blood flow. Acta Oto-laryngologica, 122(8), 808-15.
Hoshijima H, Makimoto K. Decrease in Cochlear Blood Flow With Infusion of Nitric Oxide Synthase Inhibitor and Its Recovery With L-arginine Infusion: Comparison With Abdominal Blood Flow and Auricular Blood Flow. Acta Otolaryngol. 2002;122(8):808-15. PubMed PMID: 12542197.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Decrease in cochlear blood flow with infusion of nitric oxide synthase inhibitor and its recovery with L-arginine infusion: comparison with abdominal blood flow and auricular blood flow. AU - Hoshijima,Hideaki, AU - Makimoto,Kazuo, PY - 2003/1/25/pubmed PY - 2003/4/11/medline PY - 2003/1/25/entrez SP - 808 EP - 15 JF - Acta oto-laryngologica JO - Acta Otolaryngol VL - 122 IS - 8 N2 - We observed changes in cochlear blood flow (CoBF), abdominal blood flow (AbBF) and auricular blood flow (AuBF) in rats after administration of the nitric oxide (NO) synthase inhibitor N-nitro-L-arginine-methyl ester (L-NAME). Ten min after i.v. infusion of L-NAME, L-arginine, a substrate of NO, was infused (100 mg/kg) intravenously. Using a laser Doppler flowmeter, changes in blood flow were recorded from the basal turn of the right cochlea, abdominal wall or right auricle, and systemic blood pressure (BP) was recorded simultaneously from the left femoral artery. As another parameter of vascular response, vascular conductance (VC) was calculated from blood flow/mean BP. I.v. infusion of L-NAME produced a dose-dependent depression of cochlear VC at concentrations of 0.2 (-18.9%), 1 (-37.9%), 5 (-45.8%) and 10 mg/kg (-48.3%). Infusion of L-arginine partially reversed the decrease of CoBF caused by L-NAME. The group that received a 0.2 mg/kg infusion of L-NAME showed the largest degree of recovery (23.8%) with L-arginine, while the 10 mg/kg group showed the smallest degree of recovery (10.1%). AbBF also decreased after infusion of L-NAME (5 mg/kg) but to a lesser degree (-41.1% depression of VC) and with no significance compared to the decrease in CoBF (5 mg/kg L-NAME). Likewise, AuBF showed a decrease (-44.0% depression of VC) after infusion of L-NAME (10 mg/kg), the decrease being less than that of CoBF (10 mg/kg L-NAME). Recoveries from these decreased levels of VC in the AbBF and AuBF groups appeared to be smaller than those in the CoBF groups at the same dose of L-NAME (5.5% vs 17.3% in abdominal VC; 5.3% vs 10.1% in auricular VC). In a previous study comparing the CoBF changes caused by i.v. infusion and round window application of L-NAME, we proposed that i.v. infusion of L-NAME in rats primarily affects the precapillary arteriole of the spiral modiolar artery, which effectively regulates cochlear microcirculation as a resistance artery. Thus we assume that there may exist an active pathway of the NO/soluble guanylate cyclase/cyclic guanosine monophosphate system in the above vessels. With regard to the finding of a smaller recovery of VC with L-arginine in both the AbBF and AuBF groups, we consider that differences in L-arginine availability or uptake, and in the synthesis of NO, may exist between the cochlear and cutaneous vasculatures. SN - 0001-6489 UR - https://www.unboundmedicine.com/medline/citation/12542197/Decrease_in_cochlear_blood_flow_with_infusion_of_nitric_oxide_synthase_inhibitor_and_its_recovery_with_L_arginine_infusion:_comparison_with_abdominal_blood_flow_and_auricular_blood_flow_ DB - PRIME DP - Unbound Medicine ER -