Vomeronasal organ

Vomeronasal organ
Frontal section of nasal cavities of a human embryo 28 mm long (vomeronasal organ labeled at right)
Details
PrecursorNasal placode
LymphNode
Identifiers
Latinorganum vomeronasale
MeSHD019147
TA98A06.1.02.008
TA23141
FMA77280
Anatomical terminology

The vomeronasal organ (VNO), or Jacobson's organ, is the paired auxiliary olfactory (smell) sense organ located in the soft tissue of the nasal septum, in the nasal cavity just above the roof of the mouth (the hard palate) in various tetrapods.[1] The name is derived from the fact that it lies adjacent to the unpaired vomer bone (from Latin vomer 'plowshare', for its shape) in the nasal septum. It is present and functional in all snakes and lizards, and in many mammals, including cats, dogs, cattle, pigs, and some primates. Some humans may have physical remnants of a VNO, but it is vestigial and non-functional.

The VNO contains the cell bodies of sensory neurons which have receptors that detect specific non-volatile (liquid) organic compounds which are conveyed to them from the environment. These compounds emanate from prey, predators, and the compounds called sex pheromones from potential mates. Activation of the VNO triggers an appropriate behavioral response to the presence of one of these three.

VNO neurons are activated by the binding of certain chemicals to their G protein-coupled receptors: they express receptors from three families, called V1R,[2][3][4] V2R, and FPR.[5][6] The axons from these neurons, called cranial nerve zero (CN 0), project to the accessory olfactory bulb, which targets the amygdala and bed nucleus of the stria terminalis, which in turn project to the anterior hypothalamus. These structures constitute the accessory olfactory system.

The VNO triggers the flehmen response in some mammals, which helps direct liquid organic chemicals to the organ. The VNO was discovered by Frederik Ruysch prior to 1732, and later by Ludwig Jacobson in 1813.[7]

  1. ^ Nakamuta S, Nakamuta N, Taniguchi K, Taniguchi K. Histological and ultrastructural characteristics of the primordial vomeronasal organ in lungfish. Anat Rec (Hoboken). 2012 Mar;295(3):481-91. doi: 10.1002/ar.22415. Epub 23 January 2012 PMID 22271496.
  2. ^ Dulac C, Axel R (October 1995). "A novel family of genes encoding putative pheromone receptors in mammals". Cell. 83 (2): 195–206. doi:10.1016/0092-8674(95)90161-2. PMID 7585937. S2CID 18784638.
  3. ^ Matsunami H, Buck LB (August 1997). "A multigene family encoding a diverse array of putative pheromone receptors in mammals". Cell. 90 (4): 775–784. doi:10.1016/s0092-8674(00)80537-1. PMID 9288756. S2CID 14898961.
  4. ^ Ryba NJ, Tirindelli R (August 1997). "A new multigene family of putative pheromone receptors". Neuron. 19 (2): 371–379. doi:10.1016/S0896-6273(00)80946-0. hdl:11381/2435950. PMID 9292726. S2CID 18615918.
  5. ^ Cite error: The named reference Rivière_2009 was invoked but never defined (see the help page).
  6. ^ Liberles SD, Horowitz LF, Kuang D, Contos JJ, Wilson KL, Siltberg-Liberles J, et al. (June 2009). "Formyl peptide receptors are candidate chemosensory receptors in the vomeronasal organ". Proceedings of the National Academy of Sciences of the United States of America. 106 (24): 9842–9847. Bibcode:2009PNAS..106.9842L. doi:10.1073/pnas.0904464106. PMC 2690606. PMID 19497865.
  7. ^ Jacobson, L. (1813). Anatomisk Beskrivelse over et nyt Organ i Huusdyrenes Næse. Veterinær=Selskapets Skrifter [in Danish] 2,209–246.