Peri-arterial Autonomic Innervation of the Human Ear

Abstract

Auricular vasomotor responses are considered to be signs of clinical conditions including migraine. The mechanisms of auricular vasomotor control are still debatable. This study aimed at investigating perivascular co-transmitters of vasomotor control in the auricle. Another aim was to provide three-dimensional arterial maps of the auricle, as a proxy of periarterial autonomic innervation. Twelve paired human auricles were used to visualize the arteries following Spalteholz clearing and μ-CT-based reconstruction. Perivascular innervation staining was conducted using anti-tyrosine hydroxylase (TH), anti-neuropeptide Y (NPY), anti-vasoactive intestinal peptide (VIP) and anti-choline acetyl transferase (ChAT). The combined Spalteholz technique and μ-CT revealed a highly consistent arrangement of the auricular vasculature. The superficial temporal (STA) and posterior auricular artery (PAA) supply the helical rim arcade and arcade, with the STA mainly forming the superior and the PAA forming the middle and inferior auricular artery. Co-existence of sympathetic NPY+ and TH+ terminals mediating vasoconstriction, and VIP+ and ACh+ indicating cholinergic vasodilatation, was found in the perivascular zone. The presence of both sympathetic vasoconstriction and cholinergic co-innervation for active vasodilatation was shown in the perivascular auricular zone. Assuming that the highly-consistent vasculature gives way to these terminals, this periarterial innervation may be found spread out across the helix.

NADA Ear Acupuncture and Medical Acupuncture for Pain- and Health-Related Quality of Life among Older Patients with Chronic Nonspecific Low Back Pain: A Prospective Clinical Trial

“…The ear is innervated by both the sympathetic and parasympathetic divisions of the autonomic nervous system (ANS). The sympathetic innervation of the ear arises from the superior cervical ganglion and travels to the ear via the carotid plexus [ 40 ]. The parasympathetic innervation of the ear arises from the glossopharyngeal and vagus nerves and travels to the ear via the auricular branch of the vagus nerve [ 40 ].…”

Intrinsic Auricular Muscle Zone Stimulation Improves Walking Parameters of Parkinson's Patients Faster Than Levodopa in the Motion Capture Analysis: A Pilot Study

“…Temporary modulation of blood-brain barrier permeability with stimulation of the sympathetic and parasympathetic system has been documented in the literature ( 43 , 44 ). The intrinsic auricular muscle zone also comprises the auricular sympathetic and parasympathetic zones ( 14 , 32 , 33 , 45 – 47 ). Therefore, the temporary modulation of blood-brain permeability might be the underlying mechanism of action for the most profound effect that is observed in the Combined stimulation and medication group .…”

Concerning Auricular Vagal Nerve Stimulation: Occult Neural Networks

“…In addition to the documented inhomogeneous distribution of sympathetic fibers in the human ear, the territories of the great auricular nerve, which for the most part originates in C3 with contributions from C2 (Becelli et al, 2014), and of the lesser occipital nerve, which mainly originates in C2 with contributions from C3 (Waxenbaum and Bordoni, 2019), reportedly distributes differentially across the cymba concha area (the AVNS zone) among humans. It has further been demonstrated that the Kiernan and Mitchell (1974), Chiu et al (1979), Park and Roh (2002), Liugan et al (2018), Cakmak et al (2018) and Hong et al (2019). cymba concha is innervated by the lesser occipital nerve in a quarter (26%) of participants, which indicates that the same proportion of the experimental groups of AVNS studies may exhibit inhomogeneity (Pantaloni and Sullivan, 2000).…”

“…In contrast, this distribution complicates interpretations of the AVNS because the sympathetic nerves also contribute to the perivascular innervation of the auricular arteries , and these auricular arteries have perforating branches that pierce the posterior aspect of the auricular cartilage (Figures 2C,D). These pass through to the internal aspect of the auricula and auricular skin, including the concha area where AVNS is performed (Park and Roh, 2002;Zilinsky et al, 2017;Cakmak et al, 2018). This perforating pathway provides not only a route for the sympathetic nerves to pass from the posterior surface of the ear to its anterior/interior surface but also a path for the parasympathetic axons from which the ABVN may originate.…”