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Long-term portocaval shunt and changes in rat brain amine systems
W A Fogel1, W Andrzejewski, K Sasiak
1Institute of Biogenic Amines, Polish Academy of Sciences, Lodz, Poland.
Neurobiology (Budapest, Hungary)
|July 18, 2000
Summary
Portocaval shunt in rats permanently altered brain amine systems, significantly increasing histamine and 5-hydroxyindoleacetic acid levels. Monoamine oxidase B (MAO-B) activity also rose in the hypothalamus, suggesting adaptive changes in enzyme synthesis.
Area of Science:
- Neuroscience
- Biochemistry
- Pharmacology
Background:
- Portocaval shunt (PCS) is a surgical procedure that alters blood flow and metabolite levels.
- Brain amine systems play crucial roles in neurological functions.
- Understanding PCS effects on brain chemistry is vital for neurological research.
Purpose of the Study:
- To investigate the long-term effects of portocaval shunt on brain amine systems in Wistar rats.
- To determine alterations in neurotransmitter concentrations and enzyme activities post-PCS.
Main Methods:
- Rats underwent portocaval shunt or sham operation, with brain tissue analyzed 7 months later.
- Assays included radioenzymatic, HPLC with electrochemical detection, and HPLC with fluorometry for amine quantification.
- Monoamine oxidase (MAO) A and B activities were measured using radioassays with specific inhibitors.
Main Results:
- Long-term PCS did not significantly change catecholamines, serotonin, spermidine, or spermine.
- Brain histamine and 5-hydroxyindoleacetic acid levels were significantly elevated.
- MAO-B activity increased by approximately 25% in the hypothalamus, but not in other brain regions.
Conclusions:
- Portocaval shunt induces permanent changes in specific brain amine systems.
- Elevated histamine and 5-hydroxyindoleacetic acid suggest altered serotonergic pathways.
- Increased hypothalamic MAO-B activity indicates adaptive changes in enzyme synthesis in response to altered substrate supply.