Neural regulation of the contractility of nutrient artery in the guinea pig tibia

• Published in: Pflügers Archiv Vol. 472; no. 4; pp. 481 - 494
• Main Authors: Fukuta, Hiroyasu, Mitsui, Retsu, Takano, Hiromichi, Hashitani, Hikaru
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2020; Springer Nature B.V
• Subjects: Adrenergic receptors; Animals; Arginine; Arteries; Arteries - drug effects; Arteries - physiology; Arterioles - drug effects; Arterioles - physiology; Biomedical and Life Sciences; Biomedicine; Bone remodeling; Cell Biology; Contractility; Energy metabolism; Fluoxetine; Guinea Pigs; Human Physiology; Immunohistochemistry; Innervation; Ketanserin; Male; Molecular Medicine; Muscle Contraction - physiology; Muscle Physiology; Nerves; Neurosciences; Nitric oxide; Nitric Oxide Synthase - drug effects; Nitric Oxide Synthase - metabolism; Nitric-oxide synthase; Phentolamine; Phentolamine - pharmacology; Propranolol; Receptors; Sensory neurons; Serotonin S2 receptors; Serotonin S3 receptors; Serotonin S4 receptors; Substance P; Tibia; Tibia - blood supply; Tibia - physiology; Vasodilation - drug effects; Veins & arteries; Sympathetic nerve; Nutrient artery; Serotonergic nerve; Afferent nerve
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/s00424-020-02362-9

Nutrient arteries provide the endosteal blood supply to maintain bone remodelling and energy metabolism. Here, we investigated the distribution and function of perivascular nerves in regulating the contractility of the tibial nutrient artery. Changes in artery diameter were measured using a video tracking system, while the perivascular innervation was investigated using fluorescence immunohistochemistry. Nerve-evoked phasic constrictions of nutrient arteries were suppressed by phentolamine (1 μM), an α-adrenoceptor antagonist, guanethidine (10 μM), a blocker of sympathetic transmission, or fluoxetine (10 μM), a serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitor. In arteries pretreated with guanethidine, residual nerve-evoked constrictions were abolished by a high concentration of propranolol (10 μM) that is known to inhibit 5-HT receptors, or ketanserin (100 nM), a 5-HT
2
receptor antagonist, but not SB207216 (1 μM), an antagonist of 5-HT
3
and 5-HT
4
receptors. Bath-applied 5-HT (100 nM) induced arterial constriction that was suppressed by propranolol (10 μM) or ketanserin (100 nM). Nerve-evoked arterial constrictions were enhanced by spantide (1 μM), a substance P (SP) receptor antagonist, or L-nitro arginine (L-NA; 100 μM), an inhibitor of nitric oxide synthase (NOS). Immunohistochemistry revealed 5-HT-positive nerves running along the arteries that are distinct from perivascular sympathetic or substance P-positive primary afferent nerves. For the first time, functional serotonergic nerves are identified in the tibial nutrient artery of the guinea pig. Thus, it appears that tibial nutrient arterial calibre is regulated by the balance between sympathetic and serotonergic vasoconstrictor nerves and vasodilator afferent nerves that release substance P-stimulating endothelial nitric oxide (NO) release.