1
|
Kharlamova AS, Godovalova OS, Otlyga EG, Proshchina AE. Primary and secondary olfactory centres in human ontogeny. Neurosci Res 2023; 190:1-16. [PMID: 36521642 DOI: 10.1016/j.neures.2022.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/19/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
The olfactory centres are the evolutionary oldest and most conservative area of the telencephalon. Olfactory deficiencies are involved in a large spectrum of neurologic disorders and neurodegenerative diseases. The growing interest in human olfaction has been also been driven by COVID-19-induced transitional anosmia. Nevertheless, recent data on the human olfactory centres concerning normal histology and morphogenesis are rare. Published data in the field are mainly restricted to classic studies with non-uniform nomenclature and varied definitions of certain olfactory areas. While the olfactory system in model animals (rats, mice, and more rarely non-human primates) has been extensively investigated, the developmental timetable of olfactory centres in both human prenatal and postnatal ontogeny are poorly understood and unsystemised, which complicates the process of analysing human material, including medical researches. The main purpose of this review is to provide and discuss relevant morphological data on the normal ontogeny of the human olfactory centres, with a focus on the timetable of maturation and developmental cytoarchitecture, and with special reference to the definitions and terminology of certain olfactory areas.
Collapse
Affiliation(s)
- A S Kharlamova
- Avtsyn Research Institute of Human Morphology of FSBSI "Petrovsky National Research Centre of Surgery", Tsyurupy st., 3, 117418 Moscow, Russia.
| | - O S Godovalova
- Moscow Regional Research Institute of Obstetrics and Gynecology, Pokrovka St., 22A, 101000 Moscow, Russia
| | - E G Otlyga
- Avtsyn Research Institute of Human Morphology of FSBSI "Petrovsky National Research Centre of Surgery", Tsyurupy st., 3, 117418 Moscow, Russia
| | - A E Proshchina
- Avtsyn Research Institute of Human Morphology of FSBSI "Petrovsky National Research Centre of Surgery", Tsyurupy st., 3, 117418 Moscow, Russia
| |
Collapse
|
2
|
Bruintjes TD, Bleys RLAW. The clinical significance of the human vomeronasal organ. Surg Radiol Anat 2023; 45:457-460. [PMID: 36759365 PMCID: PMC10039832 DOI: 10.1007/s00276-023-03101-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 02/02/2023] [Indexed: 02/11/2023]
Abstract
OBJECTIVE To find out whether the vomeronasal organ (VNO) can be identified in the nose as a mucosal pit in the anterior nasal septum, to elucidate its function in man and to determine whether it is important to preserve the VNO during septal surgery. METHODS Literature review. RESULTS AND CONCLUSION The VNO is histologically present in almost all humans, but a macroscopically visible septal pit does not necessarily correspond with the actual VNO. The human VNO is probably a vestigial organ with a non-operational sensory function. It is not necessary to take particular care not to damage the VNO during septal surgery.
Collapse
Affiliation(s)
- Tjasse D Bruintjes
- Department of Otorhinolaryngology, Leiden University Medical Center, Leiden, The Netherlands.
- Department of Otorhinolaryngology, Gelre Hospital Apeldoorn, Apeldoorn, The Netherlands.
| | - Ronald L A W Bleys
- Department of Anatomy, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
3
|
Gebhart VM, Rodewald A, Wollbaum E, Hertel K, Bitter T, Jirikowski GF. Evidence for accessory chemosensory cells in the adult human nasal cavity. J Chem Neuroanat 2019; 104:101732. [PMID: 31874203 DOI: 10.1016/j.jchemneu.2019.101732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 12/15/2019] [Accepted: 12/15/2019] [Indexed: 12/16/2022]
Abstract
The existence of functionally relevant accessory olfactory organs in humans is still a matter of controversy. A vomeronasal organ (VNO) with sensory and non-sensory epithelia exists only in macrosmatic mammals. A similar structure is regularly observed in humans during fetal development. The postnatal persistence of a VNO like epithelial duct has been described in about 10 %. Here we studied tissue samples of nasal mucosa from adults. In all individuals we found epithelial cells in the lower part of the nasal septum which exhibited morphological features of sensory neurons and which showed immunostaining for olfactory marker protein OMP. These cells were interposed by ciliated cells, goblet cells and small intraepithelial capillaries. Only occasionally we found such cells within a morphologically defined epithelial duct. A clear separation of sensory and non-sensory epithelia could not be observed. In most cases we found OMP positive groups of cells either in epithelial cavities or just embedded in respiratory epithelium. With RT-PCR we could confirm the presence of OMP encoding mRNA thus supporting the idea of intrinsic expression of this protein in the nasal mucosa. We conclude that accessory chemosensory structures are regularly conserved in adult humans in the approximate anatomical location of the VNO of microsmatic animals. Their functional importance is yet to be determined.
Collapse
Affiliation(s)
| | - Andrea Rodewald
- Institute of Anatomy II, Jena University Hospital, Jena, Germany
| | - Enrico Wollbaum
- Institute of Anatomy I, Jena University Hospital, Jena, Germany
| | - Kay Hertel
- Institute of Pathology, HELIOS Klinikum, Erfurt, Germany
| | - Thomas Bitter
- Department of Otorhinolaryngology, Jena University Hospital, Jena, Germany
| | | |
Collapse
|
4
|
Bhatnagar KP, Smith TD, Winstead W. The Human Vomeronasal Organ: Part IV. Incidence, Topography, Endoscopy, and Ultrastructure of the Nasopalatine Recess, Nasopalatine Fossa, and Vomeronasal Organ. ACTA ACUST UNITED AC 2018. [DOI: 10.1177/194589240201600611] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Background Previous reports on the human vomeronasal organ (VNO) have been inconsistent. Observations of fossae on the nasal septum have been reported as the VNO. Methods Adult human subjects (210) and cadavers (31) were examined using rigid nasal endoscopy, serial histology, and biopsy ultrastructure (5). Results The nasopalatine fossa (NPF) and the nasopalatine recess (NPR) are discrete, but variable, structures located adjacent to the VNO region. The NPF is not a vomeronasal pit. A septal mucosal pit could hide the vomeronasal duct opening. The VNO is a submucosal structure located 2–8 mm superior to the NPR and cannot be positively identified either macroscopically or endoscopically. Conclusion The VNO has long been mistaken for the NPF and septal mucosal pits. We show that serial histology is the correct method for identifying the VNO.
Collapse
Affiliation(s)
| | - Timothy D. Smith
- School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania
| | - Welby Winstead
- Surgery (Otolaryngology–Head and Neck), University of Louisville School of Medicine, Louisville, Kentucky
| |
Collapse
|
5
|
The vomeronasal organ - incidence in a Bulgarian population. The Journal of Laryngology & Otology 2016; 130:344-7. [PMID: 26831012 DOI: 10.1017/s0022215116000189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The vomeronasal organ is an accessory olfactory organ found in vertebrates that specialises in the chemoreception of pheromones. This study aimed to explore the existence and occurrence of the vomeronasal organ in adult humans. METHODS A total of 966 consecutive video recordings of out-patient nasopharyngolaryngoscopies performed at the St Marina University Hospital, Varna, Bulgaria, were retrospectively reviewed. RESULTS Data analysis showed that from the evaluable cases, the organ was evident on the left side of the nasal septum in 14.93 per cent, on the right side in 21.15 per cent and bilaterally in 2.35 per cent of cases. The vomeronasal organ was present in a total of 26.83 per cent of the investigated subjects. CONCLUSION More research should be focused on revealing the incidence and functionality of the organ, and on its preservation in surgical manipulations that affect the nasal septum and other nearby structures.
Collapse
|
6
|
Berta A, Ekdale EG, Zellmer NT, Deméré TA, Kienle SS, Smallcomb M. Eye, nose, hair, and throat: external anatomy of the head of a neonate gray whale (Cetacea, Mysticeti, Eschrichtiidae). Anat Rec (Hoboken) 2015; 298:648-59. [PMID: 25737431 DOI: 10.1002/ar.23112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/28/2014] [Accepted: 09/02/2014] [Indexed: 11/11/2022]
Abstract
Information is scarce on gray whale (Eschrichtius robustus) anatomy and that of mysticetes in general. Dissection of the head of a neonatal gray whale revealed novel anatomical details of the eye, blowhole, incisive papilla with associated nasopalatine ducts, sensory hairs, and throat grooves. Compared to a similar sized right whale calf, the gray whale eyeball is nearly twice as long. The nasal cartilages of the gray whale, located between the blowholes, differ from the bowhead in having accessory cartilages. A small, fleshy incisive papilla bordered by two blind nasopalatine pits near the palate's rostral tip, previously undescribed in gray whales, may be associated with the vomeronasal organ, although histological evidence is needed for definitive identification. Less well known among mysticetes are the numerous elongated, stiff sensory hairs (vibrissae) observed on the gray whale rostrum from the ventral tip to the blowhole and on the mandible. These hairs are concentrated on the chin, and those on the lower jaw are arranged in a V-shaped pattern. We confirm the presence of two primary, anteriorly converging throat grooves, confined to the throat region similar to those of ziphiid and physeteroid odontocetes. A third, shorter groove occurs lateral to the left primary groove. The throat grooves in the gray whale have been implicated in gular expansion during suction feeding.
Collapse
Affiliation(s)
- Annalisa Berta
- Department of Biology, San Diego State University, San Diego, California
| | | | | | | | | | | |
Collapse
|
7
|
Hummel T, Schultz S, Witt M, Hatt H. Electrical responses to chemosensory stimulation recorded from the vomeronasal duct and the respiratory epithelium in humans. Int J Psychophysiol 2011; 81:116-20. [PMID: 21619899 DOI: 10.1016/j.ijpsycho.2011.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/15/2011] [Accepted: 05/10/2011] [Indexed: 11/18/2022]
Abstract
The physiological significance of the human vomeronasal duct (VND) is still unclear. The aim of the present study was to investigate the question whether mucosal responses obtained from the VND are different from those obtained from the respiratory epithelium. There were 15 healthy subjects (8 male, 7 female; age range 19-45 years; 14 normosmic subjects, 1 anosmic subject). All subjects participated in two sessions whereby the first session was used to acquaint them with the experimental conditions. For chemical stimulation, an olfactometer was used which delivered chemical stimulants without altering mechanical or thermal conditions at the stimulated nasal mucosa. For stimulation we used substances previously reported to produce vomeronasal activation ("estra"=estra-1,3,5(10),16-tetraen-3ol and "andro"=androsta-4,16-dien-3-on); in addition, gaseous CO(2) was used as a non-odorous, relatively specific stimulant of the trigeminal nerve. Placement of electrodes either in the VND or on the respiratory epithelium was performed under endoscopical guidance. Subjects rated the overall intensity of the stimuli, the strength of trigeminally mediated sensations, and the hedonic tone of the stimulants. Responses could not be recorded from all subjects. For the remaining 7 subjects, intensity was strongest for CO(2) stimuli (p<0.001), whereas no significant difference was observed between "andro" and "estra" (p=0.33). All three stimulants produced responses at the respiratory epithelium with largest responses obtained after stimulation with CO(2). Similar findings were made for recordings inside the VND. Due to the small sample size sexual dimorphisms could not be addressed. In summary, these results seem to indicate that the presently used stimulants produce similar responses at the respiratory epithelium and in the VND which argues against a specific responsiveness of the VND epithelium to chemosensory stimuli although it has to be kept in mind that the effective sample size was small.
Collapse
Affiliation(s)
- T Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, Technical University of Dresden Medical School, Dresden, Germany.
| | | | | | | |
Collapse
|
8
|
Ubeda-Bañon I, Pro-Sistiaga P, Mohedano-Moriano A, Saiz-Sanchez D, de la Rosa-Prieto C, Gutierrez-Castellanos N, Lanuza E, Martinez-Garcia F, Martinez-Marcos A. Cladistic analysis of olfactory and vomeronasal systems. Front Neuroanat 2011; 5:3. [PMID: 21290004 PMCID: PMC3032080 DOI: 10.3389/fnana.2011.00003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 01/11/2011] [Indexed: 12/02/2022] Open
Abstract
Most tetrapods possess two nasal organs for detecting chemicals in their environment, which are the sensory detectors of the olfactory and vomeronasal systems. The seventies’ view that the olfactory system was only devoted to sense volatiles, whereas the vomeronasal system was exclusively specialized for pheromone detection was challenged by accumulating data showing deep anatomical and functional interrelationships between both systems. In addition, the assumption that the vomeronasal system appeared as an adaptation to terrestrial life is being questioned as well. The aim of the present work is to use a comparative strategy to gain insight in our understanding of the evolution of chemical “cortex.” We have analyzed the organization of the olfactory and vomeronasal cortices of reptiles, marsupials, and placental mammals and we have compared our findings with data from other taxa in order to better understand the evolutionary history of the nasal sensory systems in vertebrates. The olfactory and vomeronsasal cortices have been re-investigated in garter snakes (Thamnophis sirtalis), short-tailed opossums (Monodelphis domestica), and rats (Rattus norvegicus) by tracing the efferents of the main and accessory olfactory bulbs using injections of neuroanatomical anterograde tracers (dextran-amines). In snakes, the medial olfactory tract is quite evident, whereas the main vomeronasal-recipient structure, the nucleus sphaericus is a folded cortical-like structure, located at the caudal edge of the amygdala. In marsupials, which are acallosal mammals, the rhinal fissure is relatively dorsal and the olfactory and vomeronasal cortices relatively expanded. Placental mammals, like marsupials, show partially overlapping olfactory and vomeronasal projections in the rostral basal telencephalon. These data raise the interesting question of how the telencephalon has been re-organized in different groups according to the biological relevance of chemical senses.
Collapse
Affiliation(s)
- Isabel Ubeda-Bañon
- Laboratorio de Neuroplasticidad y Neurodegeneración, Departamento de Ciencias Médicas, Centro Regional de Investigaciones Biomédicas, Facultad de Medicina de Ciudad Real, Universidad de Castilla-la Mancha Ciudad Real, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Witt M, Hummel T. Vomeronasal versus olfactory epithelium: is there a cellular basis for human vomeronasal perception? INTERNATIONAL REVIEW OF CYTOLOGY 2006; 248:209-59. [PMID: 16487792 DOI: 10.1016/s0074-7696(06)48004-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The vomeronasal organ (VNO) constitutes an accessory olfactory organ that receives chemical stimuli, pheromones, which elicit behavioral, reproductive, or neuroendocrine responses among individuals of the same species. In many macrosmatic animals, the morphological substrate constitutes a separate organ system consisting of a vomeronasal duct (ductus vomeronasalis, VND), equipped with chemosensory cells, and a vomeronasal nerve (nervus vomeronasalis, VNN) conducting information into the accessory olfactory bulb (AOB) in the central nervous system (CNS). Recent data require that the long-accepted dual functionality of a main olfactory system and the VNO be reexamined, since all species without a VNO are nevertheless sexually active, and species possessing a VNO also can sense other than "vomeronasal" stimuli via the vomeronasal epithelium (VNE). The human case constitutes a borderline situation, as its embryonic VNO anlage exerts a developmental track common to most macrosmatics, but later typical structures such as the VNN, AOB, and probably most of the chemoreceptor cells within the still existent VND are lost. This review also presents recent information on the VND including immunohistochemical expression of neuronal markers, intermediate filaments, lectins, integrins, caveolin, CD44, and aquaporins. Further, we will address the issue of human pheromone candidates.
Collapse
Affiliation(s)
- Martin Witt
- Department of Anatomy, University of Technology Dresden, Dresden, Germany
| | | |
Collapse
|
10
|
Zosel AE, Smith MM, Smith TL, Castillo M. Enlarged vomeronasal organ in a child: imaging findings. Clin Imaging 2005; 28:356-9. [PMID: 15471669 DOI: 10.1016/s0899-7071(03)00242-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Indexed: 10/26/2022]
Abstract
The vomeronasal organ is a special sensory organ that exists in both animals and humans. It is located on the sides of nasal septum and although it involutes with age, occasionally it may be seen in humans. We present the imaging findings in a child with an enlarged nasal septum whose features we believe are compatible with a vomeronasal organ.
Collapse
Affiliation(s)
- Amy E Zosel
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | | | | | | |
Collapse
|
11
|
Smith TD, Bhatnagar KP, Bonar CJ, Shimp KL, Mooney MP, Siegel MI. Ontogenetic characteristics of the vomeronasal organ in Saguinus geoffroyi and Leontopithecus rosalia, with comparisons to other primates. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2003; 121:342-53. [PMID: 12884316 DOI: 10.1002/ajpa.10165] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
It has been suggested that the variability of the primate vomeronasal organ (VNO) may be greater than previously thought, especially among New World monkeys. It is not clear to what extent VNO variation reflects ontogenetic, functional, or phylogenetic differences among primates. The present study investigated VNO anatomy in an ontogenetic series of two genera of callitrichid primates, in order to assess recent attempts to develop VNO character states and to examine the evidence for VNO functionality at different life stages. A sample of six Leontopithecus rosalia, one L. chrysomelas, and six Saguinus geoffroyi was serially sectioned and stained using various methods. Two adult Callithrix jacchus were also sectioned for comparative purposes. The VNO of each primate was examined by light microscopy along its entire rostrocaudal extent. VNOs of the tamarins were described to determine whether they fit into 1 of 3 character states recently attributed to various New World monkeys. At birth, the two species of tamarins differed in the nature of communication between the VNO and nasopalatine duct (NPD). Two of 3 neonatal S. geoffroyi exhibited a fused VNO duct in a more dorsal position (adjacent to the nasal cavity) compared to that of L. rosalia. The VNO duct communicated with the NPD and was patent in neonatal L. rosalia. Both species appeared to have an age-related increase in the amount of sensory epithelium in the VNO. Subadult L. rosalia had caudal regions of the VNO that were exceptionally well-developed, similar to those of strepsirhine primates. Compared to subadults, all adult callitrichids appeared to have more ventral communications of the VNO duct directly into the NPD. Adult S. geoffroyi and L. chrysomelas both had VNO sensory epithelium separated by multiple patches of nonsensory epithelium. This contrasted with the VNOs of C. jacchus, which had a nearly continuous distribution of receptors on all surfaces of the VNO. The findings indicate that tamarins have delayed maturation of the VNO epithelium, and that some species have little or no perinatal function. These results also suggest that ontogenetic changes in craniofacial form may alter the position of the VNO in tamarins. The present study supports the use of at least two character states to categorize the VNO of various callitrichids, but it is suggested that one of these, previously called "reduced sensory epithelium" should be instead termed "interrupted sensory epithelium." The distribution of VNO sensory epithelium does not appear to reflect phylogenetic influences; it is more likely a functional characteristic that varies throughout postnatal life. Therefore, this chemosensory system has a high degree of plasticity relating to age and function, which in some instances can confound the use of characteristics as phylogenetic traits. Further study is needed to quantify VNO receptors in various species to determine if functional differences exist and if some species have more precocious VNO function than others.
Collapse
Affiliation(s)
- Timothy D Smith
- School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania 16057, USA.
| | | | | | | | | | | |
Collapse
|
12
|
Bhatnagar KP, Smith TD. The human vomeronasal organ. V. An interpretation of its discovery by Ruysch, Jacobson, or Kölliker, with an English translation of Kölliker (1877). ANATOMICAL RECORD. PART B, NEW ANATOMIST 2003; 270:4-15. [PMID: 12884838 DOI: 10.1002/ar.b.10001] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The vomeronasal organs (VNOs) of mammals are highly variable epithelial structures found bilaterally in the mucosa of the nasal septum. Whereas the discovery of the human VNO is traditionally ascribed to Frederick Ruysch (1703, 1724), the organ is named after Ludwig Levin Jacobson (1811, 1813) who described it in nonhuman mammals. We recently have pointed out controversies surrounding the incidence and structure of the enigmatic human VNO, and herein, we provide a historical analysis of its discovery. We present evidence that the honor of discovering the human VNO truly belongs to Kölliker (1877), and not to Ruysch. Ruysch illustrated the lateral view of a 2-year-old infant's nasal septum, and it is unclear whether the right nasal passage, the tubular VNO or its opening, or an unrelated duct is being indicated. Jacobson reported the VNO to be missing in humans. Its discovery in the human embryo can be related in part to later authors, such as Dursy (1869). Our reappraisal of the literature confirms that Kölliker was actually the first among these 18th-689th century investigators to provide evidence of the human VNO as a histologically identifiable structure in the fetus and the adult.
Collapse
|
13
|
Smith TD, Bhatnagar KP, Shimp KL, Kinzinger JH, Bonar CJ, Burrows AM, Mooney MP, Siegel MI. Histological definition of the vomeronasal organ in humans and chimpanzees, with a comparison to other primates. THE ANATOMICAL RECORD 2002; 267:166-76. [PMID: 11997886 DOI: 10.1002/ar.10095] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The vomeronasal organ (VNO) is a chemosensory structure that has morphological indications of functionality in strepsirhine and New World primates examined to date. In these species, it is thought to mediate certain socio-sexual behaviors. The functionality and even existence of the VNO in Old World primates has been debated. Most modern texts state that the VNO is absent in Old World monkeys, apes, and humans. A recent study on the VNO in the chimpanzee (Smith et al., 2001b) challenged this notion, demonstrating the need for further comparative studies of primates. In particular, there is a need to establish how the human/chimpanzee VNO differs from that of other primates and even nonhomologous mucosal ducts. Histochemical and microscopic morphological characteristics of the VNO and nasopalatine duct (NPD) were examined in 51 peri- and postnatal primates, including humans, chimpanzees, five species of New World monkeys, and seven strepsirhine species. The nasal septum was removed from each primate and histologically processed for coronal sectioning. Selected anteroposterior intervals of the VNO were variously stained with alcian blue (AB)-periodic acid-Schiff (PAS), PAS only, Gomori trichrome, or hematoxylin-eosin procedures. All strepsirhine species had well developed VNOs, with a prominent neuroepithelium and vomeronasal cartilages that nearly surrounded the VNO. New World monkeys had variable amounts of neuroepithelia, whereas Pan troglodytes and Homo sapiens had no recognizable neuroepithelium or vomeronasal nerves (VNNs). Certain unidentified cell types of the human/chimpanzee VNO require further examination (immunohistochemical and electron microscopic). The VNOs of P. troglodytes, H. sapiens, and New World monkeys exhibited different histochemistry of mucins compared to strepsirhine species. The nasopalatine region showed great variation among species. It is a blind-ended pit in P. troglodytes, a glandular recess in H. sapiens, a mucous-producing duct in Otolemur crassicaudatus, and a stratified squamous passageway in all other species. This study also revealed remarkable morphological/histochemical variability in the VNO and nasopalatine regions among the primate species examined. The VNOs of humans and chimpanzees had some structural similarities to nonhomologous ciliated gland ducts seen in other primates. However, certain distinctions from the VNOs of other primates or nonhomologous epithelial structures characterize the human/chimpanzee VNO: 1) bilateral epithelial tubes; 2) a superiorly displaced position in the same plane as the paraseptal cartilages; 3) a homogeneous, pseudostratified columnar morphology with ciliated regions; and 4) mucous-producing structures in the epithelium itself.
Collapse
Affiliation(s)
- Timothy D Smith
- School of Physical Therapy, College of Health and Human Services, Slippery Rock University, Slippery Rock, PA 16057, USA.
| | | | | | | | | | | | | | | |
Collapse
|