The vomeronasal system of the wolf (Canis lupus signatus): The singularities of a wild canid.

Wolves, akin to their fellow canids, extensively employ chemical signals for various aspects of communication, including territory maintenance, reproductive synchronisation and social hierarchy signalling. Pheromone-mediated chemical communication operates unconsciously among individuals, serving as an innate sensory modality that regulates both their physiology and behaviour. Despite its crucial role in the life of the wolf, there is a lacuna in comprehensive research on the neuroanatomical and physiological underpinnings of chemical communication within this species. This study investigates the vomeronasal system (VNS) of the Iberian wolf, simultaneously probing potential alterations brought about by dog domestication. Our findings demonstrate the presence of a fully functional VNS, vital for pheromone-mediated communication, in the Iberian wolf. While macroscopic similarities between the VNS of the wolf and the domestic dog are discernible, notable microscopic differences emerge. These distinctions include the presence of neuronal clusters associated with the sensory epithelium of the vomeronasal organ (VNO) and a heightened degree of differentiation of the accessory olfactory bulb (AOB). Immunohistochemical analyses reveal the expression of the two primary families of vomeronasal receptors (V1R and V2R) within the VNO. However, only the V1R family is expressed in the AOB. These findings not only yield profound insights into the VNS of the wolf but also hint at how domestication might have altered neural configurations that underpin species-specific behaviours. This understanding holds implications for the development of innovative strategies, such as the application of semiochemicals for wolf population management, aligning with contemporary conservation goals.

A revised conceptual framework for mouse vomeronasal pumping and stimulus sampling.

The physiological performance of any sensory organ is determined by its anatomy and physical properties. Consequently, complex sensory structures with elaborate features have evolved to optimize stimulus detection. Understanding these structures and their physical nature forms the basis for mechanistic insights into sensory function. Despite its crucial role as a sensor for pheromones and other behaviorally instructive chemical cues, the vomeronasal organ (VNO) remains a poorly characterized mammalian sensory structure. Fundamental principles of its physico-mechanical function, including basic aspects of stimulus sampling, remain poorly explored. Here, we revisit the classical vasomotor pump hypothesis of vomeronasal stimulus uptake. Using advanced anatomical, histological, and physiological methods, we demonstrate that large parts of the lateral mouse VNO are composed of smooth muscle. Vomeronasal smooth muscle tissue comprises two subsets of fibers with distinct topography, structure, excitation-contraction coupling, and, ultimately, contractile properties. Specifically, contractions of a large population of noradrenaline-sensitive cells mediate both transverse and longitudinal lumen expansion, whereas cholinergic stimulation targets an adluminal group of smooth muscle fibers. The latter run parallel to the VNO's rostro-caudal axis and are ideally situated to mediate antagonistic longitudinal constriction of the lumen. This newly discovered arrangement implies a novel mode of function. Single-cell transcriptomics and pharmacological profiling reveal the receptor subtypes involved. Finally, 2D/3D tomography provides non-invasive insight into the intact VNO's anatomy and mechanics, enables measurement of luminal fluid volume, and allows an assessment of relative volume change upon noradrenergic stimulation. Together, we propose a revised conceptual framework for mouse vomeronasal pumping and, thus, stimulus sampling.

Sensory neurobiology: Muscles power pheromone sensation.

While we understand how the five main sensory organs enable and facilitate stimulus detection, little is known about how the vomeronasal organ enables pheromone sensation. A new study finds specialized muscles poised to coordinate stimulus delivery, dynamics, and arousal.

Neural basis for pheromone signal transduction in mice.

Pheromones are specialized chemical messengers used for inter-individual communication within the same species, playing crucial roles in modulating behaviors and physiological states. The detection mechanisms of these signals at the peripheral organ and their transduction to the brain have been unclear. However, recent identification of pheromone molecules, their corresponding receptors, and advancements in neuroscientific technology have started to elucidate these processes. In mammals, the detection and interpretation of pheromone signals are primarily attributed to the vomeronasal system, which is a specialized olfactory apparatus predominantly dedicated to decoding socio-chemical cues. In this mini-review, we aim to delineate the vomeronasal signal transduction pathway initiated by specific vomeronasal receptor-ligand interactions in mice. First, we catalog the previously identified pheromone ligands and their corresponding receptor pairs, providing a foundational understanding of the specificity inherent in pheromonal communication. Subsequently, we examine the neural circuits involved in processing each pheromone signal. We focus on the anatomical pathways, the sexually dimorphic and physiological state-dependent aspects of signal transduction, and the neural coding strategies underlying behavioral responses to pheromonal cues. These insights provide further critical questions regarding the development of innate circuit formation and plasticity within these circuits.

Deciphering the chemical language of inbred and wild mouse conspecific scents.

In most mammals, conspecific chemosensory communication relies on semiochemical release within complex bodily secretions and subsequent stimulus detection by the vomeronasal organ (VNO). Urine, a rich source of ethologically relevant chemosignals, conveys detailed information about sex, social hierarchy, health, and reproductive state, which becomes accessible to a conspecific via vomeronasal sampling. So far, however, numerous aspects of social chemosignaling along the vomeronasal pathway remain unclear. Moreover, since virtually all research on vomeronasal physiology is based on secretions derived from inbred laboratory mice, it remains uncertain whether such stimuli provide a true representation of potentially more relevant cues found in the wild. Here, we combine a robust low-noise VNO activity assay with comparative molecular profiling of sex- and strain-specific mouse urine samples from two inbred laboratory strains as well as from wild mice. With comprehensive molecular portraits of these secretions, VNO activity analysis now enables us to (i) assess whether and, if so, how much sex/strain-selective 'raw' chemical information in urine is accessible via vomeronasal sampling; (ii) identify which chemicals exhibit sufficient discriminatory power to signal an animal's sex, strain, or both; (iii) determine the extent to which wild mouse secretions are unique; and (iv) analyze whether vomeronasal response profiles differ between strains. We report both sex- and, in particular, strain-selective VNO representations of chemical information. Within the urinary 'secretome', both volatile compounds and proteins exhibit sufficient discriminative power to provide sex- and strain-specific molecular fingerprints. While total protein amount is substantially enriched in male urine, females secrete a larger variety at overall comparatively low concentrations. Surprisingly, the molecular spectrum of wild mouse urine does not dramatically exceed that of inbred strains. Finally, vomeronasal response profiles differ between C57BL/6 and BALB/c animals, with particularly disparate representations of female semiochemicals.

Do fossorial water voles have a functional vomeronasal organ? A histological and immunohistochemical study.

The fossorial water vole, Arvicola scherman, is an herbivorous rodent that causes significant agricultural damages. The application of cairomones and alarm pheromones emerges as a promising sustainable method to improve its integrated management. These chemical signals would induce stress responses that could interfere with the species regular reproductive cycles and induce aversive reactions, steering them away from farmlands and meadows. However, there is a paucity of information regarding the water vole vomeronasal system, both in its morphological foundations and its functionality, making it imperative to understand the same for the application of chemical communication in pest control. This study fills the existing gaps in knowledge through a morphological and immunohistochemical analysis of the fossorial water vole vomeronasal organ. The study is primarily microscopic, employing two approaches: histological, using serial sections stained with various dyes (hematoxylin-eosin, Periodic acid-Schiff, Alcian blue, Nissl), and immunohistochemical, applying various markers that provide morphofunctional and structural information. These procedures have confirmed the presence of a functional vomeronasal system in fossorial water voles, characterized by a high degree of differentiation and a significant expression of cellular markers indicative of active chemical communication in this species.

Órgano vomeronasal: estudio anatómico de prevalencia y su función / The vomeronasal organ: anatomic study of prevalence and its role

Introducción: El órgano vomeronasal (OVN) descrito por Jacobson en mamíferos distintos al ser humano, es una incógnita tanto en lo que se refiere a su localización así como a su función en la raza humana. Se considera como un vestigio del olfato, que en los animales mamíferos parece influir en los hábitos sexuales (feromonas) y sociales. Hasta la fecha han sido escasos los estudios concluyentes al respecto en humanos. Objetivo: Conocer la prevalencia del órgano vomeronasal en nuestras consultas. Material y método: Presentamos un estudio prospectivo de prevalencia de la frecuencia de aparición de dicho órgano en 150 sujetos distribuidos por edad y sexo, explorados por endoscopia nasosinusal rígida. Por otro lado, analizamos la influencia sobre la libido (normal-disminuida-aumentada) en el posoperatorio de 35 septoplastías, a los 15 días tras retirada de taponamiento nasal y a los 30 días y lo comparamos con un grupo de 40 pacientes intervenidos timpanoplastías. Resultados: Estudiados 150 sujetos, encontramos la presencia del órgano vomeronasal en el 39,33% (59), de los cuales el 72,88% (43) fue unilateral (23 derecha y 20 izquierda) y el 27,12% (16) bilateral. En 91 (60,67%) no hallamos dicha estructura. La libido de los 35 pacientes intervenidos de septoplastía estaba disminuida, a los 15 días, en el 77,14% (27) frente al 40% (16) de las timpanoplastías, normal en el 17,14% (6) frente al 50% (20) de las cirugías otológicas, y en 2 (5,7%) poseptoplastía había aumentado, frente al 10% (4) del otro grupo. A los 30 días, en el 77,14% (27) de las septoplastías se había normalizado frente al 90% (36) del grupo otológico, en 2 (5,71%) de la cirugía nasal continuaba disminuida frente al 10% (4) del grupo de las timpanoplastías y en 6 (17,14%) tras septoplastía había aumentado. A todos los pacientes se les aplicó el mismo test no normalizado. Conclusión: El órgano vomeronasal de Jacobson continúa siendo un gran desconocido. Es una estructura que, al parecer, no es constante, al menos a la exploración endoscópica nasosinusal. Es difícil valorar si la cirugía en sí misma o el trauma psicológico posquirúrgico son los que afectan la libido de los pacientes tras la cirugía.

Introduction: The vomeronasal organ (OVN) described by Jacobson in mammals other than humans is unknown both in terms of its location and its role in the human race. It is viewed as a vestige of smell, that mammals in the animal seems to influence the sexual habits (pheromone) and social. To date, few studies have been inconclusive on this in humans. Aim: To determine the prevalence of vomeronasal organ in our medical consultations. Materials and methods: We report a prospective prevalence study of the occurrence of such a body in 150 subjects distributed by age and sex explored by endoscopic sinus rigid. On the other hand, we analyze the effect on the libido (normally less-plus) in the postoperative 35 septoplasty, 15 days after the withdrawal of nasal pack and 30 days and compared with a group of 40 tympanoplasty surgery. Results: Studied 150 subjects, we found the presence of the vomeronasal organ in 39.33% (59), of which 72.88% (43) had unilateral (23 right and 20 left) and 27.12% (16) bilaterally. In 91 (60.67%) did not find such a structure. The libido of the 35 patients who underwent septoplasty was decreased at 15 days, at 77.14% (27) versus 40% (16) of tympanoplasty, normal in 17.14% (6) compared to 50% (20) of otologic surgery, and in 2 (5.7%) postseptoplasty had increased, compared to 10% (4) the other group. At 30 days, in 77.14% (27) of the septoplasty group the libido was normalized against 90% (36) in the otologic group. In 2 cases (5.71%) of nasal surgery group was still decreased versus 10% (4) of cases of the tympanoplasty group, and in 6 (17.14%) postseptoplasty was increased. All patients were administered the same test is not standardized. Conclusion: The vomeronasal organ of Jacobson remains the great unknown. It is a structure that apparently is not constant, at least in the endoscopic sinus exploration. With regard to their role, it is difficult to assess whether the psychological trauma after surgery or the surgery by itself is responsible of the libido changes.

El órgano vomeronasal humano: [revisión] / Human vomeronasal organ: [revision]

El órgano vomeronasal (OVN) es una estructura que estudiamos alguna vez en anatomía, sin embargo su ubicación, frecuencia y función específica en humanos ha sido poco estudiada. Por este motivo se realizó una revisión bibliográfica actualizada acerca del OVN humano, enfatizando en puntos importantes como su anatomía y relación con algunas conductas. Hoy en día es considerado como un órgano olfatorio accesorio, capaz de percibir la presencia de vomeroferinas. Estas corresponden a un grupo de sustancias químicas identificadas, capaces de provocar cambios conductuales tanto a nivel social, sexual como maternal. Se localiza lateralmente al septo nasal y posee células periféricas, capaces de actuar como receptores, los cuales al ser estimuladas son capaces de generar una respuesta, susceptible de ser medida a través de un electrodo ubicado en el epitelio vomeronasal. Los últimos estudios sugieren que además tendría una conexión directa hacia el sistema nervioso central, mediante neuronas sensoriales bipolares, lo que implica un cuidado adicional en pacientes sometidos a cirugías cercanas a su ubicación.

The human vomeronasal organ (OVN) is a structure that is once studied in Anatomy, but commonly Iittie is known about its location, frequency and specific function. For this reason recent literature on the subject was reviewed, emphasizing important topics such as its anatomy and relation to some behaviors. The vomeronasal organ is nowadays considered an accessory olfactory organ, capable of detecting the presence of vomeropherins. These belong to a group of identified chemical substances, capable of induce behavioral changes at the social, sexual and maternal level. It is located lateral to the nasal septum, and it contains peripheral cells that act as receptors, which upon stimulation are capable of triggering a response that can be recorded via an electrode located in the vomeronasal epithelium. In addition, recent studies suggest that the vomeronasal organ has a direct connection to the central nervous system, by way of bipolar sensory neurons, which would demand additional care in patients having surgery in its vicinity.