Reflex patterns in postganglionic vasoconstrictor neurons following chronic nerve lesions

Area of Science:

• Neuroscience
• Physiology
• Pain Research

Background:

• Reflex sympathetic dystrophy involves painful disorders and trophic changes linked to limb nerve lesions.
• The hypothesis posits that abnormal postganglionic neuron discharge patterns cause these symptoms.

Purpose of the Study:

• To investigate reflex patterns in postganglionic vasoconstrictor neurons supplying skin (CVC) and skeletal muscle (MVC) in cat hindlimbs after peripheral nerve lesions.
• To compare these patterns with control preparations without nerve lesions.

Main Methods:

• Various peripheral nerve lesions were created in cat hindlimbs, including cutting, ligating, nerve grafting, and deafferentation.
• Responses of CVC and MVC neurons were analyzed after stimulation of arterial chemoreceptors, baroreceptors, and cutaneous nociceptors.

Main Results:

• In animals with specific nerve lesions (a and b), many CVC neurons exhibited altered reflex patterns, behaving similarly to MVC neurons, a statistically significant difference from controls.
• MVC neurons generally maintained their reflex patterns across lesion types.
• Deafferentation (lesion e) reduced the inhibitory influence of arterial baroreceptors on CVC activity.

Conclusions:

• Peripheral nerve lesions can induce significant alterations in the reflex activity of vasoconstrictor neurons supplying the skin.
• These changes in CVC neuron reflex patterns may contribute to the pathophysiology of conditions like reflex sympathetic dystrophy.