Peptide containing nerves in the nasal mucosa

Area of Science:

• Neuroscience
• Anatomy
• Physiology

Background:

• Nasal mucosa harbors diverse nerve fibers, including those containing vasoactive intestinal peptide (VIP), substance P (SP), and avian pancreatic polypeptide (APP).
• These nerve fibers are typically associated with blood vessels and glands, with SP also present in the epithelium.
• The pterygopalatine ganglion is a key neural structure containing nerve cell bodies positive for acetylcholinesterase (AChE), VIP, and SP.

Purpose of the Study:

• To investigate the presence and distribution of VIP, SP, and APP nerve fibers in the mammalian nasal mucosa.
• To determine the relationship between these neurochemical markers and acetylcholinesterase (AChE) in the pterygopalatine ganglion.
• To elucidate the role of VIP and SP as mediators of nasal mucosal vasodilation.

Main Methods:

• Immunohistochemistry was used to identify and localize VIP, SP, and APP containing nerve fibers.
• Acetylcholinesterase (AChE) staining was performed on sections of the pterygopalatine ganglion.
• The effects of colchicine exposure on AChE, VIP, and SP expression in nerve cell bodies were examined.

Main Results:

• VIP and SP containing nerve fibers are abundant in the nasal mucosa, particularly around blood vessels and glands.
• SP containing fibers are also found within the nasal epithelium.
• Nerve cell bodies in the pterygopalatine ganglion stained positive for AChE, VIP, and SP. Colchicine treatment revealed that VIP and SP positive nerve cell bodies also express AChE.
• VIP and SP were identified as potent mediators of atropine-resistant vasodilation in the nasal mucosa.

Conclusions:

• VIP and SP are significant neurotransmitters in the nasal mucosa, playing a crucial role in regulating vascular tone.
• The pterygopalatine ganglion serves as a source for these peptidergic nerve fibers.
• While VIP and SP functions are partly understood, the physiological role of APP in the nasal mucosa remains unknown.