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Lateral hypothalamic lesions and norepinephrine turnover in rats
The Journal of Clinical Investigation
|September 1, 1983
Summary
Lateral hypothalamic lesions cause rapid weight loss and increase norepinephrine turnover in key organs, effects that persist for weeks. This contrasts with paraventricular lesions, highlighting the lateral hypothalamus's role in metabolic regulation.
Area of Science:
- Neuroscience
- Metabolic Regulation
- Physiology
Background:
- The lateral hypothalamus (LH) plays a critical role in regulating feeding behavior and energy balance.
- Norepinephrine (NE) turnover is a key indicator of sympathetic nervous system activity and metabolic rate.
- Understanding the impact of hypothalamic lesions on metabolic processes is crucial for comprehending energy homeostasis.
Purpose of the Study:
- To investigate the effects of lateral hypothalamic (LH) lesions on weight loss, norepinephrine (NE) turnover, and gastric integrity in rats.
- To compare the metabolic and physiological responses to LH lesions with those of sham-operated controls and rats with cerebral cortical lesions.
- To determine the persistence of altered NE turnover following LH lesions.
Main Methods:
- Surgical induction of lateral hypothalamic lesions and sham operations in rats.
- Measurement of body weight loss following lesioning and fasting.
- Assessment of norepinephrine turnover rates in interscapular brown adipose tissue, heart, and pancreas using radiolabeled tracers.
- Examination of gastric mucosa for erosions and hemorrhages.
Main Results:
- Rats with LH lesions exhibited significantly greater weight loss compared to sham-operated and cerebral cortex-lesioned rats.
- LH lesions acutely increased NE turnover threefold to ninefold in brown adipose tissue, heart, and pancreas, an effect that persisted for 3 weeks.
- Cold exposure increased NE turnover in sham-operated rats but not in LH-lesioned rats; LH-lesioned rats also showed gastric erosions.
Conclusions:
- Lateral hypothalamic lesions induce a rapid increase in norepinephrine turnover and significant weight loss, suggesting a disruption in metabolic control.
- The observed increase in NE turnover is acute and sustained for at least 3 weeks post-lesioning.
- LH lesions appear to impair the physiological response to cold and compromise gastric mucosal integrity.
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