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Glucocorticoid stimulation interacts with sympathetic innervation to affect cardiac development in oculo
1Department of Psychology, University of Alabama at Birmingham 35294, USA.
Pediatric Research
|October 1, 1995
Summary
Glucocorticoids enhance growth of innervated developing heart muscle, but can harm non-innervated muscle. Sympathetic innervation influences how glucocorticoids affect heart development.
Area of Science:
- Cardiovascular Biology
- Developmental Biology
- Endocrinology
Background:
- Myocardial development is influenced by hormonal and neural factors.
- Glucocorticoids and sympathetic innervation play critical roles in tissue development.
- Understanding their interplay is crucial for comprehending cardiac growth regulation.
Purpose of the Study:
- To investigate the combined effects of glucocorticoids and sympathetic innervation on developing myocardium.
- To determine how glucocorticoid stimulation or blockade impacts myocardial growth in the presence or absence of sympathetic innervation.
Main Methods:
- Embryonic rat hearts were grafted into the anterior eye chamber of adult rats (in oculo model).
- Grafts were exposed to chronic dexamethasone (glucocorticoid stimulation) or RU 486 (glucocorticoid receptor blockade).
- Sympathetic innervation was manipulated via unilateral superior cervical ganglionectomy.
Main Results:
- Dexamethasone increased size and weight of sympathetically innervated grafts.
- RU 486 significantly decreased graft weight in innervated grafts.
- Dexamethasone decreased graft size in denervated grafts, while RU 486 had no effect.
- No differences in graft beating rate were observed across conditions.
Conclusions:
- Sympathetic innervation modulates glucocorticoid effects on developing myocardium.
- Glucocorticoid exposure enhances growth of sympathetically innervated myocardium.
- Excessive glucocorticoid exposure may compromise growth of non-innervated myocardium.