Skin nerve sympathetic activity during insulin-induced hypoglycaemia

Area of Science:

• Neuroscience
• Human Physiology
• Endocrinology

Background:

• Hypoglycemia, a common complication of diabetes treatment, can trigger autonomic nervous system responses.
• Sympathetic nerve activity plays a crucial role in regulating skin blood flow and sweating, essential for thermoregulation.

Purpose of the Study:

• To investigate the specific effects of insulin-induced hypoglycemia on sympathetic nerve outflow to the skin.
• To differentiate the responses of sudomotor and vasoconstrictor pathways during hypoglycemia.

Main Methods:

• Microelectrode recordings of peroneal nerve sympathetic activity in seven healthy subjects.
• Measurements were taken at rest and for 90 minutes following insulin injection (0.15 IU/kg body weight).
• Analysis of temporal patterns in sympathetic nerve outflow.

Main Results:

• A significant increase in overall skin sympathetic nerve activity was observed during hypoglycemia.
• A notable shift in the temporal pattern of nerve outflow occurred, favoring sudomotor over vasoconstrictor activity.
• Subjects reported warmth, sweating, and vasodilation, followed by a drop in body temperature.

Conclusions:

• Hypoglycemia differentially affects sympathetic outflow, enhancing sudomotor and inhibiting vasoconstrictor signals.
• Neurally mediated thermoregulation, involving increased sweating and vasodilation, contributes to heat loss during hypoglycemia.
• This study elucidates a specific autonomic response to hypoglycemia impacting thermoregulation.