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Organ and development related difference in tissue norepinephrine concentrations in Dahl rats
Q H Chen1, Y Nishida, M S Zhou
1Second Department of Physiology, Kagawa Medical University, Japan. kgwphys1@kms.ac.jp
Journal of the Autonomic Nervous System
|October 6, 1998
Summary
Tissue norepinephrine concentration (tNE) varies significantly by organ and development in Dahl rats. Salt-sensitive rats exhibit suppressed tNE development and lower levels compared to salt-resistant rats, suggesting abnormal sympathetic nerve activity.
Area of Science:
- Physiology
- Neuroscience
- Pharmacology
Background:
- Norepinephrine (NE) is a key neurotransmitter and hormone involved in sympathetic nervous system activity.
- Dahl salt-sensitive (S) and salt-resistant (R) rats are widely used models for studying hypertension and cardiovascular regulation.
- Understanding organ-specific and developmental changes in tissue norepinephrine concentration (tNE) is crucial for elucidating physiological differences between rat strains.
Purpose of the Study:
- To investigate organ and development-related differences in tNE between Dahl S and R rats.
- To assess the impact of sinoaortic denervation (SAD) on tNE and blood pressure in these rat models.
- To explore potential links between tNE variations, blood pressure, and sympathetic nerve activity.
Main Methods:
- Measurement of tNE in 16 organs across various developmental stages (1-11 weeks) in Dahl S and R rats.
- Sinoaortic denervation (SAD) or sham operation in 5-week-old rats, with subsequent tNE and plasma NE (pNE) measurements at 9 weeks.
- Assessment of mean arterial pressure (MAP) in intact and denervated rats.
Main Results:
- Significant variations in tNE were observed across 16 organs in both rat strains, with levels ranging from bone to salivary gland.
- Dahl R rats showed a development-dependent increase in tNE in most organs, while S rats exhibited suppressed tNE development and significantly lower tNE in 14 of 16 organs.
- SAD did not significantly alter tNE in most organs, but slightly increased MAP in S rats. No significant differences in pNE were found between strains or after SAD.
Conclusions:
- Organ and developmental stage are critical determinants of tNE levels in Dahl rats.
- Dahl S rats display significantly lower and developmentally suppressed tNE compared to R rats.
- Observed tNE differences in S rats may be linked to abnormal sympathetic nerve activity rather than baroreflex sensitivity or blood pressure regulation.