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Vasoactive intestinal polypeptide and calcitonin gene-related peptide in the developing rat heart atria
1Department of Physiology, Charles University, Faculty of Medicine, Plzen, Czech Republic.
Insights
Vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP) levels in rat atria show asymmetric development. These peptide concentrations vary significantly during postnatal growth, suggesting important roles in atrial development.
Area of Science:
- Cardiovascular Physiology
- Developmental Biology
- Neuroendocrinology
Background:
- Vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP) are neuropeptides with known roles in cardiovascular regulation.
- Understanding their developmental trajectory in the heart is crucial for comprehending cardiac maturation and function.
Purpose of the Study:
- To investigate the developmental changes in VIP-like immunoreactivity (VIP-LI) and CGRP-like immunoreactivity (CGRP-LI) concentrations in the developing rat right and left atria.
- To identify any sex-specific differences or regional asymmetries in peptide levels during postnatal development.
Main Methods:
- Radioimmunoassay was employed to quantify VIP-LI and CGRP-LI concentrations.
- Samples were collected from rat right and left atria on postnatal days 1, 10, 25, 45, 60, and 85.
- Data were analyzed to assess developmental trends and regional differences.
Main Results:
- VIP-LI was detected at postnatal day 1 in both atria, with levels peaking around postnatal day 25 in the right atrium.
- Significant regional differences in VIP-LI emerged at later stages (P60, P85), with higher concentrations in the left atrium.
- CGRP-LI concentrations showed similar developmental patterns in both atria, decreasing after birth, increasing by P60, and then declining again.
Conclusions:
- The study reveals an asymmetry in the postnatal development of atrial VIP-LI and CGRP-LI concentrations between the right and left atria.
- The distinct temporal profiles of VIP and CGRP suggest unique roles and trophic functions during cardiac development.
- These findings contribute to understanding the neurochemical regulation of atrial development and maturation.
Abstract:
Vasoactive intestinal polypeptide-like immunoreactivity (VIP-LI) and calcitonin gene-related peptide (CGRP)-LI concentrations were determined in the developing rat heart atria using radioimmunoassay. Peptide levels were analysed on postnatal days 1, 10, 25, 45, 60, and 85 (P1-P85) separately in the right (RA) and left atria (LA). No sex differences were revealed at any age examined. VIP-LI has been already detected in both atria at P1 in concentrations comparable to values at P10. In the RA, VIP-LI levels increased significantly between days P10 and P25, remained high at P45 and then declined. In the LA, VIP-LI concentrations did not differ from those in the RA on days P1, P10, P25, and P45. However, regional differences were found at P60 and P85, when the peptide levels were significantly higher in the LA than in the RA. The postnatal changes in CGRP-LI concentrations were comparable in both atria with similar values at P1 and P85. After birth, CGRP levels decreased gradually till P45, then they increased till P60 and declined again at P85. The results demonstrate that there is an asymmetry in the postnatal development of the atrial VIP-LI and CGRP-LI concentrations. VIP-LI levels reached their maximum at P25, whereas CGRP-LI levels at P60. Relatively high peptide concentrations in neonatal atria and their variations during development might be related to diverse trophic functions of VIP and CGRP.