Involvement of the vomeronasal organ and prolactin in pheromonal induction of delayed implantation in mice

Abstract Variations in gene expression patterns represent a powerful source of evolutionary innovation. In a rodent living about 70 million years ago, a genomic accident led an immune formyl peptide receptor (FPR) gene to hijack a vomeronasal receptor regulatory sequence. This gene shuffling event forced an immune pathogen sensor to transition into an olfactory chemoreceptor, which thus moved from sensing the internal world to probing the outside world. We here discuss the evolution of the FPR gene family, the events that led to their neofunctionalization in the vomeronasal organ and the functions of immune and vomeronasal FPRs.

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Morphological and Histological Features of the Vomeronasal Organ in African Pygmy Hedgehog (Atelerix albiventris)

Animals ◽

10.3390/ani11051462 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1462

Author(s):

Daisuke Kondoh ◽

Yusuke Tanaka ◽

Yusuke K. Kawai ◽

Takayuki Mineshige ◽

Kenichi Watanabe ◽

...

Keyword(s):

Soft Tissues ◽

Periodic Acid ◽

Vomeronasal Organ ◽

Sensory Epithelium ◽

Middle Part ◽

Periodic Acid Schiff ◽

Histological Features ◽

Duct Opening ◽

Hematoxylin Eosin ◽

Rostral Part

The vomeronasal organ (VNO) detects specific chemicals such as pheromones and kairomones. Hedgehogs (Eulipotyphla: Erinaceidae) have a well-developed accessory olfactory bulb that receives projections from the VNO, but little is known about the hedgehog VNO. Here, we studied the histological features of the VNO in five individual African pygmy hedgehogs by hematoxylin-eosin, periodic acid-Schiff, and Alcian blue stains. The hedgehog VNO comprises a hyaline cartilage capsule, soft tissue and epithelial lumen, and it branches from the site just before the incisive duct opening into the nasal cavity. The soft tissues contain several small mucous (or mucoserous) glands and a large serous gland, and many venous sinuses all around the lumen. The VNO lumen is round to oval throughout the hedgehog VNO, and the sensory epithelium lines almost the entire rostral part and medial wall of the middle part. These findings indicate that the VNO is functional and plays an important role in the hedgehog. Notably, the VNO apparently has a characteristic flushing mechanism with serous secretions like those of gustatory glands, which the hedgehog might frequently use to recognize the external environment.

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The branches of the descending palatine artery and their relation to the vomeronasal organ inAngoragoats

Veterinární Medicína ◽

10.17221/5518-vetmed ◽

2012 ◽

Vol 51 (No. 2) ◽

pp. 55-59 ◽

Cited By ~ 2

Author(s):

K. Besoluk ◽

E. Eken ◽

S. Bahar

Keyword(s):

Vomeronasal Organ ◽

Sphenopalatine Artery ◽

Arterial Blood ◽

The Right ◽

Palatine Artery ◽

Fine Branch

The aim of this study was to reveal the branches of the descending palatine artery, and its relation to the vomeronasal organ inAngoragoats. For this purpose, ten heads of adultAngoragoats obtained from a slaughterhouse were used. The ramifications of the latex enjected descending palatine artery and their vomeronasal organ-related findings were revealed by fine dissection and transverse sections. Arterial blood reached the caudally vomeronasal organ primarily via the sphenopalatine artery, and also cranially via a fine branch of the major palatine artery by crossing the palatine fissure. The average diameters of both the descending palatine artery and its branches were thicker on the left side than on the right, and its ramifications were not variable in this species.

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I.—On the Pregnancy Rate in the Lactating Mouse and the Effect of Suckling on the Duration of Pregnancy

Proceedings of the Royal Society of Edinburgh ◽

10.1017/s0370164600022914 ◽

1932 ◽

Vol 51 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

L. Mirskaia ◽

F. A. E. Crew

Keyword(s):

Mammary Gland ◽

Corpus Luteum ◽

Pregnancy Rate ◽

Inhibitory Action ◽

Reproductive Activity ◽

Delayed Implantation ◽

Prolonged Pregnancy ◽

Suggested Explanation ◽

Duration Of Pregnancy

Summary1. The pregnancy rate of primiparæ, suckling their young, was, in this experiment, 24·1 per cent.; that of multiparæ suckling their young, 50 per cent. It is shown that this difference is not due to differences in the incidence of ovulation associated with postpartum œstrus. The suggested explanation of this difference between puberal and adult groups is that a certain level of somatic maturity is a prerequisite for full reproductive activity.2. In all cases the duration of pregnancy was prolonged. The degree of prolongation was variable and could not be related to the number of young in the uterus or suckling. The results provide no support for the suggestion that this prolongation, due to delayed implantation of the fertilised ova, is to be referred to an inhibitory action on the part of the mammary gland. The suggestion is made that the delayed implantation and prolonged pregnancy are due to inability on the part of the corpus luteum to cater adequately for implantation and lactation synchronously.

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Central role of G protein Gαi2 and Gαi2+ vomeronasal neurons in balancing territorial and infant-directed aggression of male mice

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1821492116 ◽

2019 ◽

Vol 116 (11) ◽

pp. 5135-5143 ◽

Cited By ~ 16

Author(s):

Anne-Charlotte Trouillet ◽

Matthieu Keller ◽

Jan Weiss ◽

Trese Leinders-Zufall ◽

Lutz Birnbaumer ◽

...

Keyword(s):

G Protein ◽

Sensory Neurons ◽

Neural Activity ◽

Parental Behavior ◽

Vomeronasal Organ ◽

Male Infant ◽

Lateral Septum ◽

Male Mice ◽

Protein Subunit ◽

Α Subunit

Aggression is controlled by the olfactory system in many animal species. In male mice, territorial and infant-directed aggression are tightly regulated by the vomeronasal organ (VNO), but how diverse subsets of sensory neurons convey pheromonal information to limbic centers is not yet known. Here, we employ genetic strategies to show that mouse vomeronasal sensory neurons expressing the G protein subunit Gαi2 regulate male–male and infant-directed aggression through distinct circuit mechanisms. Conditional ablation of Gαi2 enhances male–male aggression and increases neural activity in the medial amygdala (MeA), bed nucleus of the stria terminalis, and lateral septum. By contrast, conditional Gαi2 ablation causes reduced infant-directed aggression and decreased activity in MeA neurons during male–infant interactions. Strikingly, these mice also display enhanced parental behavior and elevated neural activity in the medial preoptic area, whereas sexual behavior remains normal. These results identify Gαi2 as the primary G protein α-subunit mediating the detection of volatile chemosignals in the apical layer of the VNO, and they show that Gαi2+ VSNs and the brain circuits activated by these neurons play a central role in orchestrating and balancing territorial and infant-directed aggression of male mice through bidirectional activation and inhibition of different targets in the limbic system.

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