Physiological responses to insulin hypoglycaemia in spinal man

Area of Science:

• Neuroscience
• Endocrinology
• Physiology

Background:

• Spinal cord injury (SCI) can profoundly affect autonomic nervous system function.
• Hypoglycemia triggers distinct physiological responses in healthy individuals, mediated by the autonomic nervous system and hormonal changes.
• Previous research has not fully elucidated the autonomic and endocrine responses to hypoglycemia in individuals with high cervical SCI.

Purpose of the Study:

• To investigate the physiological responses to fish insulin-induced hypoglycemia in tetraplegic subjects with complete cervical spinal cord transection.
• To compare these responses with those typically observed in non-injured individuals.

Main Methods:

• Nine tetraplegic subjects with complete cervical spinal cord transection (C4-C8) were studied.
• Hypoglycemia was induced using fish insulin.
• Physiological parameters including blood pressure, heart rate, plasma adrenaline, and plasma human insulin levels were monitored.

Main Results:

• Hypoglycemia led to a reduction in both systolic and diastolic blood pressure in tetraplegic subjects, contrasting with normal responses.
• A rise in heart rate was observed during hypoglycemia.
• The typical increase in plasma adrenaline levels was absent.
• Plasma human insulin levels were suppressed.
• Tetraplegic subjects did not exhibit the usual neuroglycopenic symptoms associated with hypoglycemia.

Conclusions:

• Complete cervical spinal cord transection significantly alters the physiological and hormonal responses to hypoglycemia.
• The autonomic counter-regulatory response to hypoglycemia appears to be impaired in tetraplegic individuals.
• Further research is needed to understand the long-term implications and potential management strategies for hypoglycemia in this population.