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Repeated (isolation) stress increases tribulin-like activity in the rat
I Armando1, A P Lemoine, M Ferrini
1Centro de Investigaciones Endocrinologicas, Hospital de Ninos R. Gutierrez, Buenos Aires, Argentina.
Cellular and Molecular Neurobiology
|March 1, 1989
Summary
Repeated isolation stress initially increases tribulin in rat brains but decreases with adaptation. Peripheral tribulin and catecholamine levels rise later, suggesting a role in stress response and maintaining elevated catecholamines.
Area of Science:
- Neuroscience
- Biochemistry
- Stress Physiology
Background:
- Monoamine oxidase (MAO) inhibitory activity, known as tribulin, is implicated in stress and anxiety.
- Catecholamines (dopamine, epinephrine, norepinephrine) are key neurotransmitters involved in the stress response.
Purpose of the Study:
- To investigate the impact of repeated isolation stress on tribulin activity in rat tissues.
- To examine the effect of this stress paradigm on plasma catecholamine levels.
Main Methods:
- Rats were subjected to daily 9-minute isolation stress.
- Animals were sacrificed on days 1, 2, 4, and 5 post-stress initiation.
- MAO inhibitory activity (tribulin) and plasma catecholamine levels were measured in brain, cerebellum, heart, kidney, and plasma.
Main Results:
- Central nervous system tribulin increased initially (days 1-2) and then decreased (days 4-5), suggesting adaptation.
- Peripheral tribulin (heart, kidney) levels peaked later (days 4-5).
- Plasma dopamine, epinephrine, and norepinephrine levels showed significant increases at various time points, with norepinephrine elevated from day 2 onwards.
Conclusions:
- Repeated isolation stress induces a transient increase in central nervous system tribulin, potentially related to adaptation.
- Peripheral tribulin changes occur later and show no adaptation within the study period.
- Tribulin may play a dual role in stress, possibly promoting anxiety and contributing to elevated circulating catecholamines.