Morphology and Chemical Phenotype of the Ovarian Intrinsic Neurons in Neonate and Sexually Mature Reproductive Guinea Pig

Abstract

Introduction: The existence of ovarian intrinsic neurons is well established. However, the morphology and chemical phenotype are not completely characterized and are even unknown for some species used in medical research. The purpose of this work was to determine the morphology and chemical phenotype of intrinsic neurons of the guinea pig ovary at two ages: neonates (0 days old) and sexually mature reproductive animals (90 days old). Materials and Methods: For the morphological analysis, we employed the modified Golgi-Cox impregnation technique. For the chemical phenotype, we used immunohistochemistry and the following antibodies; tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), transient receptor potential type 1 (TRPV1), neuron-specific nuclear protein (NeuN) and proto-oncogene product of the cFos gene (cFos). We also used enzyme histochemistry for NADPH-diaphorase detection. Results: The number of intrinsic neurons in the neonate ovary was low in comparison to the adult guinea pig ovary. The intrinsic neurons were located in the cortex and the ovarian medulla; some were isolated or clustered, forming ganglia, and others were interconnected and formed networks. The neurons were small, medium or large. In the cortex of neonate vs adult ovaries, the small and medium neurons comprised 23% vs 36% and 5.2% vs 11.6%, respectively. In the medulla, the percent of the same neurons was 10.1% vs 10.1% and 1.1% vs 2.2% in the neonate and adult, respectively. In both cortex and medulla < 1% were large neurons at two ages. Also, the neurons were rounded, fusiform or multipolar. In the cortex, they were 12.7% vs 20.9%, 14.9% vs 24.2% and 1.1% vs 3.0%, respectively. In the medulla, the percent of small vs medium neurons was 6% vs 7.1% and 4.1% vs 4.8% in the neonate and adult ovary, respectively, and <1% were large neurons at both ages. The chemical phenotypes were in the neonate and adult: TH/NeuN-positive neurons, 16.3% vs 26.5%; CGRP/NeuN, 13.5% vs 35.8%; TRPV1/NeuN, 10.2% vs 38.6%; and cFos/NeuN, 4.6% vs 5.4%, re-* Corresponding author. F. Luna et al. 14 spectively. The percent of NADPHd-positive cells in the cortex was 9.5% vs 25.1% and 3.2% vs 62.2% in the medulla in the neonate and adult, respectively. Conclusion: Altogether, these data showed that the number of ovarian intrinsic neurons was low at birth and increased in the sexually mature reproductive guinea pig. The chemical phenotype was rich and peptidergic, catecholaminergic and nitrergic in nature and positive for cFos immunoreactivity. Therefore, intrinsic neurons can be chemical sensors inside of the gonad and transmit signal to the central nervous system.

Three-Dimensional and Two-Dimensional Relationships of Gangliogenesis With Folliculogenesis in Mature Mouse Ovary: A Golgi-Cox Staining Approach

“…Consistent with our ndings on the relationship between ovarian function and gangliogenesis, the same ndings about other neuronal cells in mice [24,10], monkeys and humans [9,25] demonstrated that ovarian internal neuronal laments increased in sexual maturation. Furthermore, distribution, morphology, and chemical phenotype of ovarian intrinsic nervous system in guinea pigs increase in adult animals compared with neonates [16]. Comparing previous ndings with our results, it can be speculated that follicular function has a positive relationship with gangliogenesis, intrinsic neuronal network and vasculogenesis.…”

Three-dimensional and two-dimensional relationships of gangliogenesis with folliculogenesis in mature mouse ovary: a Golgi–Cox staining approach

“…These nerves and ganglia are responsible for ovarian estradiol secretion 15 . The number of internal neurons in neonatal ovaries was lower than that of adult ovaries, some of which form ganglia and networks 16 .…”

“…Consistent with our findings on the relationship between ovarian function and gangliogenesis, the same findings about other neuronal cells in mice 10 , 24 , monkeys and humans 9 , 25 demonstrated that ovarian internal neuronal filaments increased in sexual maturation. Furthermore, distribution, morphology, and chemical phenotype of ovarian intrinsic nervous system in guinea pigs increase in adult animals compared with neonates 16 . Comparing previous findings with our results, it can be speculated that follicular function has a positive relationship with gangliogenesis, intrinsic neuronal network and vasculogenesis.…”

Ganglionic and non-ganglionic neurons in frog heart: do they differ?

“…Although somata of catecholaminergic and peptidergic neurons have been reported in the mudpuppy, Necturus maculosus [10,11], there is no evidence yet on non-cholinergic neuronal somata in the heart of anuran amphibians. Nonetheless, it has been shown previously in mammalian autonomic ganglia that the population of cholinergic neurons is not uniform, as many of those neurons express additional transmitters and diff er electrophysiologically [7,9]. Considerable heterogeneity has been reported in the morphological, neurochemical, and electrophysiological properties of neurons in the sympathetic ganglia [4,6].…”