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Interaction between pressor and depressor areas in cat ventrolateral medulla
1Department of Pharmacology, Howard University College of Medicine, Washington, DC 20059.
Brain Research
|June 21, 1991
Summary
Stimulating the caudal depressor area (CA) lowers blood pressure (BP) by increasing GABA release in the intermediate pressor area (IA). Blocking GABA receptors reversed this effect, confirming a GABAergic pathway in BP regulation.
Area of Science:
- Neuroscience
- Cardiovascular Physiology
Background:
- The central nervous system plays a crucial role in regulating blood pressure (BP).
- Specific medullary areas are known to influence BP, but the precise neurotransmitter pathways are not fully elucidated.
Purpose of the Study:
- To investigate if stimulating the caudal depressor area (CA) reduces BP by enhancing GABA release in the intermediate pressor area (IA).
Main Methods:
- Excitotoxic lesioning with kainic acid (KA) was applied to the CA to lower BP.
- GABA receptor antagonists (picrotoxin, bicuculline) were applied to the IA.
- The effect of antagonists alone and after KA stimulation was compared.
- A glycine receptor antagonist (strychnine) was used as a control.
Main Results:
- KA application to the CA significantly lowered BP.
- Subsequent IA application of picrotoxin or bicuculline reversed the hypotensive effect.
- The BP-raising effect of GABA antagonists was significantly potentiated after CA stimulation.
- Strychnine did not produce a similar potentiation.
Conclusions:
- These findings indicate a GABAergic input from the CA to the IA.
- This pathway is involved in the central control of blood pressure in cats.