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Quantifying Acute Changes in Renal Sympathetic Nerve Activity in Response to Central Nervous System Manipulations in Anesthetized Rats
Published on: September 11, 2018
Endogenous norepinephrine regulates blood flow to the intact rat tibia
J B A Feitelson1, E Kulenovic, D J Beck
1Department of Physiology & Biophysics, School of Medicine, University of Louisville, KY 40292, USA.
Summary
Endogenous norepinephrine (NE) constricts bone blood vessels. Blocking alpha-adrenergic receptors increased tibia blood flow, indicating NE
Area of Science:
- Physiology
- Pharmacology
- Vascular Biology
Background:
- Norepinephrine (NE) is a key neurotransmitter.
- Its role in regulating basal bone blood flow is not fully understood.
Purpose of the Study:
- To investigate the role of endogenous norepinephrine in controlling basal blood flow to intact bone.
- To determine if alpha-adrenergic receptors mediate vasoconstriction in the bone vasculature.
Main Methods:
- Bone blood flow was measured in anesthetized rats using laser Doppler flowmetry.
- Alpha-adrenergic receptors were blocked using phentolamine or phenoxybenzamine.
- Norepinephrine was administered to assess its effects on bone blood flow.
Main Results:
- Norepinephrine injection caused a dose-dependent decrease in bone blood flow.
- Alpha-adrenergic receptor blockade significantly attenuated the norepinephrine-induced vasoconstriction.
- Blocking alpha-adrenergic receptors alone decreased bone vascular resistance.
Conclusions:
- Endogenous norepinephrine exerts a tonic constrictor effect on tibial blood vessels.
- Alpha-adrenergic receptors play a significant role in regulating basal bone blood flow.
- These findings contribute to understanding vascular control mechanisms in bone.
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