Supersensitivity in rat micro-arteries after short-term denervation

Area of Science:

• Vascular biology and neurophysiology.
• Smooth muscle physiology and pharmacology.

Background:

• Nerve damage can alter vascular reactivity.
• The medial plantar artery's response to denervation is not fully understood.

Purpose of the Study:

• To investigate the effects of short-term denervation on the contractile responses of rat medial plantar artery.
• To determine if complete denervation leads to vascular smooth muscle supersensitivity.

Main Methods:

• In vitro investigation of microvascular preparations from rat medial plantar artery.
• Surgical resection of saphenous and/or sciatic nerves in vivo.
• Immunocytochemistry to assess nerve fiber density (NPY, CGRP).
• Wire myography to measure contractile responses to phenylephrine and high-potassium (high-K+).

Main Results:

• Resection of both saphenous and sciatic nerves led to a complete loss of NPY and CGRP immunoreactive nerve fibers.
• Vessels with complete denervation showed significantly increased sensitivity to phenylephrine and high-K+.
• Denervated vessels exhibited enhanced sensitivity to extracellular Ca2+ when depolarized.

Conclusions:

• Complete short-term denervation of the rat medial plantar artery induces pronounced vascular smooth muscle supersensitivity.
• This supersensitivity involves alpha-receptors and cellular excitation-contraction coupling.
• Altered vascular reactivity post-denervation may contribute to in vivo vascular disturbances.