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Updated: Jun 4, 2026
09:56
Implantation of Combined Telemetric ECG and Blood Pressure Transmitters to Determine Spontaneous Baroreflex Sensitivity in Conscious Mice
Published on: February 14, 2021
GABA in the paraventricular nucleus tonically suppresses baroreflex function: alterations during pregnancy
Mollie C Page1, Priscila A Cassaglia, Virginia L Brooks
1Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, 97239, USA.
Summary
GABAergic inputs to the paraventricular nucleus of the hypothalamus normally suppress baroreflex function. This GABAergic inhibition is reduced during pregnancy, impacting heart rate and sympathetic nerve activity regulation.
Area of Science:
- Neuroscience
- Cardiovascular Physiology
- Neuroendocrinology
Background:
- GABAergic inputs to the paraventricular nucleus of the hypothalamus (PVN) are known to suppress heart rate and sympathetic nerve activity.
- The role of GABA in modulating PVN control of baroreflex function remains unexplored.
Purpose of the Study:
- To investigate whether GABAergic inhibition in the PVN affects baroreflex function.
- To determine if pregnancy alters the influence of GABA on PVN-mediated baroreflex control.
Main Methods:
- Microinjection of the GABA(A) antagonist bicuculline into the PVN of anesthetized virgin and pregnant rats.
- Measurement of baroreflex gain and maximum heart rate and lumbar sympathetic nerve activity.
Main Results:
- In virgin rats, PVN bicuculline administration significantly increased baroreflex gain and maximum heart rate and sympathetic nerve activity.
- Pregnancy was associated with decreased heart rate baroreflex gain compared to virgin rats.
- PVN bicuculline administration produced smaller increases in baroreflex gain and maximum heart rate in pregnant rats compared to virgin rats.
Conclusions:
- The PVN normally exerts tonic GABAergic inhibition on baroreflex function.
- This GABAergic inhibition of the baroreflex is diminished during pregnancy.
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