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Ingrowth of sympathetic innervation occurs concomitantly with a decrease of ANP in the growing rat cardiac ventricles
M Hansson1, U Kjörell, S Forsgren
1Department of Integrative Medical Biology, Umeå University, Sweden. magnus.hansson@anatomy.umu.se
Anatomy and Embryology
|February 24, 2001
Summary
Sympathetic nerve growth in the heart reduces atrial natriuretic peptide (ANP) levels. Destroying these nerves early increases ANP, showing sympathetic innervation influences cardiac ANP expression.
Area of Science:
- Cardiovascular Physiology
- Developmental Biology
- Neurocardiology
Background:
- Atrial natriuretic peptide (ANP) plays a role in cardiovascular homeostasis.
- Sympathetic innervation influences cardiac function and development.
Purpose of the Study:
- To investigate the relationship between sympathetic nerve development and ANP expression in the growing rat heart.
- To determine the effect of sympathetic nerve destruction on cardiac ANP levels.
Main Methods:
- Immunohistochemistry for ANP and tyrosine hydroxylase (sympathetic nerves) at postnatal days 0, 7, 14, and 21.
- Radioimmunoassay to measure cardiac ANP content after chemical sympathectomy in neonatal rats.
Main Results:
- A reciprocal pattern observed: ANP expression decreased as tyrosine hydroxylase-positive sympathetic innervation increased in the ventricular myocardium.
- Marked ANP immunoexpression and scarce innervation in the peripheral Purkinje fiber network.
- Chemical sympathectomy led to elevated cardiac ANP levels.
Conclusions:
- Sympathetic innervation development in the ventricles correlates with declining ANP expression during cardiac maturation.
- Early destruction of sympathetic nerves increases cardiac ANP levels, suggesting sympathetic innervation influences ANP.
- Cardiac ANP levels in the ventricular myocardium and conduction system are modulated by sympathetic innervation.