Differences in autonomic innervation to the vertebrobasilar arteries in spontaneously hypertensive and Wistar rats

• Published in: The Journal of physiology 2018-08, Vol.596 (16), p.3505-3529
• Main Authors: Roloff, Eva v. L., Walas, Dawid, Moraes, Davi J. A., Kasparov, Sergey, Paton, Julian F. R.
• Format: Article
• Language: English
• Subjects: Acetylcholine; Animals; Arteries; Autonomic nervous system; Autonomic Nervous System - physiopathology; Basilar Artery - innervation; Basilar Artery - metabolism; Blood pressure; Brain stem; Cardiovascular; cerebrovascular resistance; Denervation; Developmental stages; Fibers; Functional anatomy; Ganglia; Hypertension; Hypertension - physiopathology; Immunofluorescence; Immunohistochemistry; Innervation; Intestine; Male; Norepinephrine; parasympathetic innervation; Parasympathetic nervous system; rat; Rats; Rats, Inbred SHR; Rats, Wistar; Research Paper; Rodents; sympathetic innervation; Sympathetic nerves; Vasoactive agents; Vasoactive intestinal peptide; Vasodilation; Veins & arteries; Vertebral Artery - innervation; Vertebral Artery - metabolism; vertebral/basilar arteries; Vesicular acetylcholine transporter
• ISSN: 0022-3751; 1469-7793
• DOI: 10.1113/JP275973

Key points Essential hypertension is associated with hyperactivity of the sympathetic nervous system and hypoperfusion of the brainstem area controlling arterial pressure. Sympathetic and parasympathetic innervation of vertebrobasilar arteries may regulate blood perfusion to the brainstem. We examined the autonomic innervation of these arteries in pre‐hypertensive (PHSH) and hypertensive spontaneously hypertensive (SH) rats relative to age‐matched Wistar rats. Our main findings were: (1) an unexpected decrease in noradrenergic sympathetic innervation in PHSH and SH compared to Wistar rats despite elevated sympathetic drive in PHSH rats; (2) a dramatic deficit in cholinergic and peptidergic parasympathetic innervation in PHSH and SH compared to Wistar rats; and (3) denervation of sympathetic fibres did not alter vertebrobasilar artery morphology or arterial pressure. Our results support a compromised vasodilatory capacity in PHSH and SH rats compared to Wistar rats, which may explain their hypoperfused brainstem. Neurogenic hypertension may result from brainstem hypoperfusion. We previously found remodelling (decreased lumen, increased wall thickness) in vertebrobasilar arteries of juvenile, pre‐hypertensive spontaneously hypertensive (PHSH) and adult spontaneously hypertensive (SH) rats compared to age‐matched normotensive rats. We tested the hypothesis that there would be a greater density of sympathetic to parasympathetic innervation of vertebrobasilar arteries in SH versus Wistar rats irrespective of the stage of development and that sympathetic denervation (ablation of the superior cervical ganglia bilaterally) would reverse the remodelling and lower blood pressure. Contrary to our hypothesis, immunohistochemistry revealed a decrease in the innervation density of noradrenergic sympathetic fibres in adult SH rats (P