Norepinephrine release and reuptake by hypothalamic synaptosomes of spontaneously hypertensive rats
We compared the overflow of endogenous norepinephrine during electrical field stimulation, the norepinephrine content, and the rate of initial neuronal uptake of (3H)norepinephrine in synaptosomes isolated from hypothalamus and brainstem of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats at 7 and 13 weeks of age. The synaptosomes of two rats, a SHR and a WKY rat control, were simultaneously processed and subjected to the same electrical field stimulation. The overflow of endogenous norepinephrine during electrical stimulation (2 Hz, 2 minutes) in the hypothalamic synaptosomes of 7-week-old SHR was significantly greater, whereas the overflow of 13-week-old SHR was equivalent to the age-matched WKY rat. The norepinephrine content of synaptosomes was about the same in SHR and age-matched controls. There was also significantly enhanced (3H)norepinephrine uptake in the hypothalamic synaptosomes of young SHR, but neither the hypothalamic nor the brainstem samples of 13-week-old SHR showed any significant difference in their rate of (3H)norepinephrine uptake. These data are similar to those we observed (unpublished observations) in perfused mesenteric artery system in which norepinephrine release was significantly elevated during periarterial nerve stimulation only in young SHR. Thus, these results suggest that a parallel enhancement of norepinephrine release in hypothalamus with that of peripheral nervous system may play an important role during development of hypertension in young SHR.
- Research Organization:
- Univ. of Southern California, Los Angeles (USA)
- OSTI ID:
- 6325200
- Journal Information:
- Hypertension (Dallas); (United States), Journal Name: Hypertension (Dallas); (United States) Vol. 13:3; ISSN HPRTD
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AGE DEPENDENCE
ANIMAL CELLS
ANIMALS
BODY
BRAIN
CARDIOVASCULAR DISEASES
CENTRAL NERVOUS SYSTEM
DISEASES
HYPERTENSION
HYPOTHALAMUS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
NERVE CELLS
NERVOUS SYSTEM
ORGANS
PATHOGENESIS
RATS
RODENTS
SECRETION
SOMATIC CELLS
STIMULI
SYMPTOMS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UPTAKE
VASCULAR DISEASES
VERTEBRATES