Related Experiment Videos
Eicosanoid synthesis elicited by norepinephrine in piglet parietal cortex
Brain Research
|February 17, 1987
Summary
Norepinephrine constricts piglet pial arteries, stimulating eicosanoid release. These eicosanoids, like prostaglandin E2, then limit the norepinephrine-induced constriction, revealing a protective cerebrovascular feedback loop.
Area of Science:
- Neuroscience
- Pharmacology
- Physiology
Background:
- Cerebral blood flow regulation is crucial for brain function.
- The role of vasoactive substances in neonatal cerebral circulation requires further elucidation.
Purpose of the Study:
- To investigate the effects of norepinephrine and isoproterenol on pial arterial diameter.
- To examine the impact of these agents on cerebral eicosanoid synthesis in newborn pigs.
Main Methods:
- Anesthetized newborn pigs were used to study pial arterial responses.
- Norepinephrine and isoproterenol were administered topically in artificial cerebrospinal fluid (CSF).
- Eicosanoid levels (6-keto-prostaglandin F1 alpha, thromboxane B2, prostaglandin E2) in CSF were measured.
Main Results:
- Norepinephrine constricted pial arteries and increased CSF eicosanoid concentrations.
- Prostaglandin E2 demonstrated significant pial arterial dilation.
- Indomethacin potentiated norepinephrine-induced constriction, while isoproterenol caused dilation without altering eicosanoids.
Conclusions:
- Norepinephrine stimulates the release of prostanoids from the cortical surface.
- These released prostanoids act as a feedback mechanism to limit cerebrovascular constriction induced by norepinephrine.