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Alterations in brain monoaminergic functioning associated with septal lesion induced hyperreactivity
Pharmacology, Biochemistry, and Behavior
|January 1, 1975
Summary
Bilateral septal lesions in rats increased reactivity to handling, accompanied by reduced hypothalamic norepinephrine and dopamine. This suggests a role for catecholamines in affective behavior, but not altered monoamine dynamics.
Area of Science:
- Neuroscience
- Behavioral Neuroscience
- Neurochemistry
Background:
- Affective behaviors are complex and influenced by various neurochemical systems.
- The septal area of the brain plays a role in regulating emotional and behavioral responses.
- Monoamines, including norepinephrine and dopamine, are implicated in mood and reactivity.
Purpose of the Study:
- To investigate the effects of bilateral septal lesions on animal reactivity and brain monoamine levels.
- To examine the relationship between septal lesions, affective behavior, and catecholamine dynamics.
Main Methods:
- Thirty male albino rats underwent behavioral testing for handling reactivity.
- Bilateral septal lesions or sham operations were performed.
- Postoperatively, monoamine levels (norepinephrine, dopamine, serotonin) and their metabolites were measured in various brain regions using fluorometry.
- Catecholamine dynamics (rate constants, turnover times, utilization rates) were assessed.
Main Results:
- Septal-lesioned rats exhibited significantly increased reactivity to handling compared to controls.
- Reduced norepinephrine and dopamine levels were observed in the hypothalamus of lesioned rats, along with decreased dopamine in the limbic system.
- Serotonin levels and catecholamine dynamics remained largely unaffected by the lesions.
- The ratio of norepinephrine to serotonin in the limbic system was significantly reduced in lesioned animals.
Conclusions:
- Septal lesions alter affective behavior and specific catecholamine levels in the brain.
- These findings support the involvement of catecholamines in affective behaviors.
- The study did not find evidence of altered functional dynamics of brain monoamines in relation to the induced hyperreactivity.
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