Participation of Central Noradrenergic Neurons in Arterial Baroreceptor Reflexes in the Rabbit
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Discussion
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Implication
Does not support practice change in hypertension; leaves open central noradrenergic mechanisms in experimental neurogenic models.
Key Points
- To determine whether central noradrenergic neurons participate in arterial baroreceptor reflex changes following sinoaortic denervation in rabbits.
- Measured intracisternally administered 3H-norepinephrine disappearance rates and tyrosine hydroxylase activity in five brain regions and three spinal cord regions.
- Assessed animals 2 weeks following surgical sectioning of the carotid sinus and aortic nerves to model neurogenic hypertension.
- Sinoaortic denervation induced neurogenic hypertension, increasing mean blood pressure by 29% and heart rate by 17% without altering endogenous catecholamine levels across the eight regions.
- Hypertensive rabbits exhibited an approximate twofold increase in 3H-norepinephrine turnover and tyrosine hydroxylase activity in the thoracolumbar spinal cord.
- Denervated rabbits showed elevated 3H-norepinephrine turnover in the hypothalamus, while tyrosine hydroxylase activity in this region remained unchanged.
Cite This Study
Chalmers et al. (1971) studied this question.