# Sympathetic Chain Ganglia in the Female Pig During Prenatal Development: Noradrenergic and Cholinergic Neurons

## TL;DR

This study examines how noradrenergic and cholinergic neurons in the sympathetic chain ganglia of pig fetuses develop during pregnancy, offering insights into autonomic nervous system development.

## Contribution

This is the first study to characterize noradrenergic and cholinergic neurotransmitter expression in porcine fetal sympathetic chain ganglia during prenatal development.

## Key findings

- At 5 weeks, 79.83% of neurons were DβH-positive, 25.90% VAChT-positive, and 12.45% co-expressed both.
- By 10 weeks, DβH-positive neurons increased to 88.5%, while VAChT-positive neurons dropped to 1.98%.
- The study reveals dynamic changes in neurotransmitter expression during prenatal development of the autonomic nervous system.

## Abstract

Due to the limited data on chemical coding of sympathetic chain ganglia neurons during the prenatal period, this study, for the first time, aimed to characterise noradrenergic and cholinergic neurotransmitter expression in lumbar sympathetic chain ganglia (L SChG) of 5-, 7-, and 10-week-old porcine foetuses as a model increasingly recognised in biomedical research. Double immunohistochemical staining was performed using antibodies against PGP 9.5 (marker of neuronal structures), β-hydroxylase tyrosine (DβH), and vesicular acetylcholine transporter (VAChT). The current findings demonstrated that, in 5-week-old foetuses, approximately 79.83 ± 4.37% of nerve cell bodies were DβH-positive, 25.90 ± 5.60% contained VAChT, and some neurons were DβH/VAChT-positive (12.45 ± 4.36%). In 7-week-old foetuses, the proportion of DβH-positive neurons increased to 82.0 ± 9.7%, while VAChT-positive neurons decreased to 6.5 ± 1.0%, and 9.1 ± 0.7% DβH-positive L SChG perikarya contained VAChT. In 10-week-old foetuses, DβH-positive neurons accounted for 88.5 ± 2.1%, VAChT-positive for 1.98 ± 0.64%, and DβH/VAChT-positive perikarya decreased to 5.4 ± 0.4%. These findings provide new insight into the differentiation of the autonomic nervous system and the timing of neurotransmitter phenotype specification. Understanding the ontogeny of noradrenergic and cholinergic neurons may contribute to a better understanding of developmental disorders affecting the autonomic nervous system and may have implications for regenerative medicine, neurodevelopmental diagnostics, and therapeutic strategies targeting sympathetic dysfunction.