Abstract
Brain stimulation or activation of certain reflexes can result in differential activation of the two populations of adrenal medullary chromaffin cells: those secreting either epinephrine or norepinephrine, suggesting that they are controlled by different central sympathetic networks. In urethan-chloralose-anesthetized rats, we found that antidromically identified adrenal sympathetic preganglionic neurons (SPNs) were excited by stimulation of the rostral ventrolateral medulla (RVLM) with either a short (mean: 29 ms) or a long (mean: 129 ms) latency. The latter group of adrenal SPNs were remarkably insensitive to baroreceptor reflex activation but strongly activated by the glucopenic agent 2-deoxyglucose (2-DG), indicating their role in regulation of adrenal epinephrine release. In contrast, adrenal SPNs activated by RVLM stimulation at a short latency were completely inhibited by increases in arterial pressure or stimulation of the aortic depressor nerve, were unaffected by 2-DG administration, and are presumed to govern the discharge of adrenal norepinephrine-secreting chromaffin cells. These findings of a functionally distinct preganglionic innervation of epinephrine- and norepinephrine-releasing adrenal chromaffin cells provide a foundation for identifying the different sympathetic networks underlying the differential regulation of epinephrine and norepinephrine secretion from the adrenal medulla in response to physiological challenges and experimental stimuli.
Original language | English (US) |
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Pages (from-to) | R1763-R1775 |
Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
Volume | 279 |
Issue number | 5 48-5 |
DOIs | |
State | Published - 2000 |
Externally published | Yes |
Keywords
- 2-deoxyglucose
- Adrenal medulla
- Blood pressure
- Hypoglycemia
- Intermediolateral nucleus
- Rostral ventrolateral medulla
- Splanchnic nerve activity
- Sympathetic nerve activity
- Vasoconstrictor neurons
ASJC Scopus subject areas
- Physiology
- Physiology (medical)