Innervation pattern of the preocular human central retinal artery

Area of Science:

• Ophthalmology
• Neuroscience
• Vascular Biology

Background:

• The central retinal artery (CRA) supplies oxygen and nutrients to the inner retina.
• The autonomic innervation of the preocular CRA, crucial for retinal blood supply, is poorly understood.
• Understanding CRA innervation is vital for both physiological and pathological conditions affecting vision.

Purpose of the Study:

• To characterize the autonomic innervation of the human preocular central retinal artery (CRA) using morphological methods.
• To investigate the presence of adrenergic, cholinergic, and peptidergic nerve fibers in the CRA wall.

Main Methods:

• Human donor eyes were used, adhering to the Declaration of Helsinki.
• Single and double immunohistochemistry was performed for various neuronal markers (TH, DBH, ChAT, VAChT, nNOS, CGRP, SP, VIP) and NADPH-diaphorase cytochemistry.
• Light, fluorescence, and confocal laser-scanning microscopy were employed for documentation.

Main Results:

• Adrenergic nerve fibers (tyrosine hydroxylase and dopamine-β-hydroxylase positive) were found in the CRA wall, but without a distinct plexus.
• Cholinergic nerve fibers (choline acetyl-transferase and vesicular acetylcholine transporter positive) were also detected.
• No significant peptidergic innervation (CGRP, SP, VIP) was observed; nNOS staining did not confirm NADPH-d findings.

Conclusions:

• The preocular human CRA possesses both sympathetic (adrenergic) and parasympathetic (cholinergic) innervation.
• A peptidergic primary afferent innervation appears to be absent in the studied segment of the CRA.
• Further research is required to elucidate the role of CRA innervation in regulating retinal perfusion, especially given evidence of intraretinal vessel autoregulation.