BACKGROUND: Circulating factors delivered to the nodose ganglion (NG) by the occipital artery (OA) have been shown to affect vagal afferent activity, and thus the contractile state of the OA may influence blood flow to the NG. METHODS: OA were isolated and bisected into proximal and distal segments relative to the external carotid artery. RESULTS: Bisection highlighted stark differences between maximal contractile responses and OA sensitivity. Specifically, maximum responses to vasopressin and the V1 receptor agonist were significantly higher in distal than proximal segments. Distal segments were significantly more sensitive to 5-hydroxytryptamine (5-HT) and the 5-HT2 receptor agonist than proximal segments. Angiotensin II (AT)2, V2 and 5-HT(1B/1D) receptor agonists did not elicit vascular responses. Additionally, AT1 receptor agonists elicited mild, yet not significantly different maximal responses between segments. CONCLUSION: The results of this study are consistent with contractile properties of rat OA being mediated via AT1, V1 and 5-HT2 receptors and dependent upon the OA segment. Furthermore, vasopressin-induced constriction of the OA, regardless of a bolus dose or a first and second concentration-response curve, retained this unique segmental difference. We hypothesize that these segmental differences may be important in the regulation of blood flow through the OA in health and disease.
BACKGROUND: Circulating factors delivered to the nodose ganglion (NG) by the occipital artery (OA) have been shown to affect vagal afferent activity, and thus the contractile state of the OA may influence blood flow to the NG. METHODS: OA were isolated and bisected into proximal and distal segments relative to the external carotid artery. RESULTS: Bisection highlighted stark differences between maximal contractile responses and OA sensitivity. Specifically, maximum responses to vasopressin and the V1 receptor agonist were significantly higher in distal than proximal segments. Distal segments were significantly more sensitive to 5-hydroxytryptamine (5-HT) and the 5-HT2 receptor agonist than proximal segments. Angiotensin II (AT)2, V2 and 5-HT(1B/1D) receptor agonists did not elicit vascular responses. Additionally, AT1 receptor agonists elicited mild, yet not significantly different maximal responses between segments. CONCLUSION: The results of this study are consistent with contractile properties of rat OA being mediated via AT1, V1 and 5-HT2 receptors and dependent upon the OA segment. Furthermore, vasopressin-induced constriction of the OA, regardless of a bolus dose or a first and second concentration-response curve, retained this unique segmental difference. We hypothesize that these segmental differences may be important in the regulation of blood flow through the OA in health and disease.
Authors: Alice C Holloway; Hongwei Qian; Luisa Pipolo; James Ziogas; Shin-ichiro Miura; Sadashiva Karnik; Bridget R Southwell; Michael J Lew; Walter G Thomas Journal: Mol Pharmacol Date: 2002-04 Impact factor: 4.436
Authors: Raphaela Verheggen; Andreas Meier; Inga Werner; Andreas Wienekamp; Thomas Kruschat; Trond Brattelid; Finn Olav Levy; Alberto Kaumann Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2004-03-06 Impact factor: 3.000
Authors: Tyler S Nelson; Zhanna Nepiyushchikh; Joshua S T Hooks; Mohammad S Razavi; Tristan Lewis; Cristina C Clement; Merrilee Thoresen; Matthew T Cribb; Mindy K Ross; Rudolph L Gleason; Laura Santambrogio; John F Peroni; J Brandon Dixon Journal: Nat Biomed Eng Date: 2019-12-23 Impact factor: 25.671