Nasal Trigeminal Chemoreception / 대한이비인후과학회지

The sensory function of the trigeminal nerve is to provide tactile, proprioceptive, and nociceptive afference by chemical stimulation. Various physical responses of the trigeminal nerve to stimuli help to defend against harmful substances. Recently, many studies have been conducted on solitary chemoreceptor cells innervated by trigeminal nerve. Most volatile organic compounds stimulate both the olfactory and trigeminal nervous systems. In general, the trigeminal nervous system is less sensitive than the olfactory nervous system. Studies have shown that sensation of the trigeminal nerve by chemical stimulation results in inhibition of olfaction. This indicates that the olfactory and trigeminal nerves interact with each other in the central nervous system. It is important to study various noxious stimuli acting on the trigeminal nerve in modern society where environmental concerns are intensifying.

Bitter Taste, Rising New Functions and Significance of Extra-oral Expressions

Taste is closely related to intake of food. Taste perception is also influenced by type of food ingested, and nutrition and health status. Bitter taste plays an important role in the survival of human and animals to avoid probable toxic and harmful substances. Vertebrate animals recognize bitter taste through type 2 taste receptors (T2Rs). Several T2Rs have been expressed extra-oral such as the gastrointestinal tract, respiratory tract, urogenital tract, brain and immune cells, and parts of their functions are being revealed. This review will discuss physiological roles of T2Rs in relation to innate immunity, secretion and smooth muscle contraction expressed in extra-oral cells and tissues, and we summarize relationships between polymorphisms in T2Rs and general or oral diseases. It is not a coincidence that animals pay much genetic costs for taste and smell during evolution.

Chemosensory age discrimination in the snake Boa constrictor (Serpentes: Boidae)

Many snakes are able to use their chemosensory system to detect scent of conspecifics, which is important in many social contexts. Age discrimination based on chemical cues may be especially important to ensure access to sexually mature potential partners. In this study, we used 24 individual Boa constrictor snakes (12 adults mature and 12 non-mature individuals) that had been captured in different areas of Ecuador, and were maintained in captivity at the Vivarium of Quito. We used tongue-flick experiments to examine whether these snakes were able to discriminate between scents from mature and non-mature individuals. Results showed that B. constrictor snakes used chemical cues to recognize conspecifics and that the scent of individuals of different ages elicited chemosensory responses of different magnitudes. The scents from adult conspecifics elicited the quickest and highest chemosensory responses (i.e., short latency times and high tongue-flick rates), although we did not find differential responses to scent of males and females. The magnitude of the responses was lower to scent of sub adult individuals, and then even lower to scent of juvenile snakes, but in all cases the scent of snakes was discriminated from a blank control. We discuss the potential chemical mechanisms that may allow age recognition and its implications for social and sexual behavior of this snake species.

Muchas serpientes son capaces de usar su sistema quimiosensorial para detectar el olor de individuos coespecíficos, lo que es importante en muchos contextos sociales. La discriminación de la edad basada en señales químicas puede ser especialmente importante para asegurar el acceso a parejas potenciales que sean sexualmente maduras. En este estudio, usamos 24 individuos de una especie de boa (Boa constrictor) (12 individuos adultos y 12 inmaduros) que habían sido capturados en diferentes partes de Ecuador y eran mantenidos en cautividad el Vivarium de Quito. Usamos experimentos de protusiones linguales para examinar si esta serpiente es capaz de discriminar entre el olor de individuos maduros y no maduros. Los resultados mostraron que B. constrictor usa señales químicas para reconocer co-específicos y que el olor de individuos de distinta edad provoca respuestas quimiosensoriales de diferente magnitud. El olor de individuos adultos provocó las respuestas más rápidas y elevadas (esto es, tiempos de latencia más cortos y tasas más altas de protusiones linguales), aunque no encontramos diferencias en las respuestas a olores de machos y hembras. La magnitud de las respuestas fue más baja a olores de sub adultos, e incluso más baja a olor de juveniles, pero en todos los casos el olor de una serpiente era discriminado de un control no oloroso. Discutimos los posibles mecanismos químicos que pueden permitir esta discriminación de la edad y sus implicaciones para el comportamiento social y sexual de esta serpiente.

Respostas comportamentais do camarão de água doce Macrobrachium amazonicum à estimulação por cloreto de amônia / Behavioural responses of the freshwater prawn Macrobrachium amazonicum to chemical with ammonium chloride

O objetivo do presente estudo foi analisar as respostas comportamentais do camarão de água doce Macrobrachium amazonicum, mediante estimulação química com cloreto de amônia a 100mM. Espécimes desse crustáceo foram posicionados em um aquário com quatro litros de água doce desclorificada, e um pulso de solução estimulante foi injetado no recipiente na extremidade oposta em relação à posição do animal. Os animais estudados não apresentaram resposta aos estímulos utilizados. Isso pode sugerir que o limiar de resposta comportamental é maior do que o limiar fisiológico dos neurônios receptivos primários, ou que o cloreto de amônia precisa ser associado com outros compostos ou determinadas variáveis físicas para poder gerar uma resposta ecológica na espécie estudada.

The objective of the present study was to analyze the behavioral responses of the freshwater prawn Macrobrachium amazonicum, elicited by stimulation with ammonium chloride at 100mM. Specimens were positioned in a four liter dechlorinated freshwater tank and a 0.5ml pulse of stimulant was applied in the opposing corner of the recipient. The studied animals demonstrated no response to the stimuli applied. This may suggest that the behavioral response threshold is higher than the physiological response threshold of the primary chemoreceptor neurons or that the ammonium chloride must be associated with other compounds or certain physical attributes in order to evoke an ethological reaction from the studied species.

Behavioural responses to human skin extracts and antennal phenotypes of sylvatic first filial generation and long rearing laboratory colony Rhodnius prolixus

Chagas disease is a major public health issue and is mainly spread by Triatominae insects (Hemiptera: Reduviidae). Rhodnius prolixus is the main vector species in Northern South America. Host-seeking behaviour in R. prolixus is mediated by different compounds that are produced by and emanate from the host or microbiota on the host's skin. We tested the behavioural responses of sylvatic first filial generation (F1) and colony insects to extracts of human skin with a dual choice olfactometer. In addition, we compared the antennal phenotypes in both populations. No statistical differences were found between the two populations at the behavioural level. Both showed a preference for face and feet extracts and this effect was abolished for face extracts after treatment with an antibacterial gel. The observation of the antennal phenotype showed that there were differences between both groups in the total length, total surface area and number and density of bristles. However, the number and density of chemoreceptive sensilla (basiconic and thin and thick-walled trichoids) and the total density of sensilla did not show statistically significant differences. These results demonstrate that colony insects, which have only been fed with living hens for the last 30 years, are attracted by human skin extracts in a similar way as F1 sylvatic insects.

Spatial choice is biased by chemical cues from conspecifics in the speckeled worm eel Myrophis punctatus

The speckeld worm eel Myrophis punctatus lives in high-densities assemblages, and usually digs through, or lies on the substrate. These behaviours could lead to chemical marks on the substrate and could modulate the spatial distribution in this species. We tested the hypothesis that the spatial choice of the speckled worm eel is modulated by the presence of conspecific odour on the substrate. Here, we showed that the speckled worm eel avoids the substrate area containing the conspecific odour, indicating that this chemical cue modulates the eel's spatial decision. The eels clearly detected the conspecific's odour. This perception might indicate the presence of conspecifics into the substrate. Since the eels avoided an area containing conspecific odour, we suggest this may be a response that avoids the consequences of invading a resident-animal's territory.

A enguia mirongo-mirim Myrophis punctatus vive em agrupamentos de alta densidade populacional e comumente se enterra ou permanece sob o substrato. Esses comportamentos podem levar a marcas químicas no subtrato e podem, portanto, modular o uso do espaço nessa espécie. Neste estudo, testamos a hipótese de que a preferência espacial da enguia mirongo-mirim é influenciada pela presença de odor do animal coespecífico no subtrato. Mostramos que as enguias evitam a área que contém tal odor, indicando que as decisões de ocupação espacial podem ser influenciadas por pistas químicas de coespecíficos. As enguias claramente detectaram o odor de um animal coespecífico e essa percepção poderia ser um indicativo da presença de um coespecífico enterrado no substrato. Visto que elas evitam uma área contendo tal odor, sugerimos que isso poderia ser uma resposta para evitar invadir o território de um animal residente.

Androgen Receptor Distribution, PAS and Alcyan Blue Reaction in the Vomeronasal Organ and the Nasal Septum Mucosa of the Developing Male Rat / Distribución del Receptor de Andrógeno, Positividad a PAS y Alcyan Blue en el Órgano Vomeronasal y la Mucosa del Tabique Nasal Durante el Desarrollo de la Rata Macho

The vomeronasal organ (VNO) is a tubular chemoreceptory organ which detects environmental pheromones and is essential for mammalian normal reproductive activity. A sensitive chemoreceptory neuroepithelium lines the concave VNO wall and the opposite, convex wall is lined by a seudostratified, receptor-free epithelium. The secretion of the Jacobson glands (JG) -tubuloacinary glands lying in the lamina propia of the VNO - is essential for pheromones contacting vomeronasal organ chemoreceptors. Tubuloacinary glands lying in the connective tissue of the nasal septum mucosa (Bowman glands), can be classified as ventral and dorsal, according to their location. Positivity to PAS and Alcyan blue reactions and androgen receptor immunolocalization was evaluated with a semiquantitative system (0,1, 2 or 3 crosses) in JG, ventral Bowman glands (VBG), dorsal Bowman glands (DBG), sensitive chemoreceptory neuroepithelium (Ne), receptor-free epithelium (RFE) and nasal septum respiratory epithelium (RE) histological slides of male rats at 5, 15, 25 and 35 days of age. The VBG and JG were intensely positive to PAS reaction since 5 days of age, and weakly positive to Alcyan blue reaction (AB) since 15 days of age, but not at 5 days of age. Both JG and VBG were strongly positive to androgen receptor immunolocalization at all ages studied (15, 25 and 35 days of age). DBG were always negative to both PAS and AB reactions. The NE and the RFE and nasal mucosa luminar epithelium were negative. To our knowledge, this is the first report of androgen receptor (AR) immunolocalization in the vomeronasal organ and the nasal septum mucosa. The present results also suggest an influence of androgens on the mechanism of pheromones contacting with the Ne of the VNO through regulation of the Jacobson glands secretion.

El órgano vomeronasal (VNO) es un órgano quimioreceptor, tubular, que detecta feromonas ambientales. Es esencial para la actividad reproductiva normal de los mamíferos. El VNO está formado por un neuroepitelio quimiosensible (pared cóncava, Ne) y un epitelio pseudoestratificado (epitelio libre de receptores: RFE) en la pared opuesta, convexa. La secreción de las glándulas tubuloacinares de Jacobson (JG), ubicadas en la lámina propia del VNO, son esenciales para que las feromonas entren en contacto con el Ne. Las glándulas tubuloacinares ubicadas en la mucosa del tabique nasal (glándulas del Bowman), se pueden clasificar como ventrales (VBG) y dorsales (DBG), según su localization. La positividad a las técnicas de PAS, Azul de Alcián (AB) e immunolocalization del receptor de andrógeno (AR), fueron evaluadas con un sistema semicuantitativo (0, 1, 2 o 3 cruces) en láminas histológicas de JG, VBG, DBG, Ne, RFE y del epitelio del tabique nasal (RE) en ratas macho de 5, 15, 25 y 35 días de edad. Las VBG y JG fueron intensamente positivas a la reacción de PAS desde los 5 días de edad y débilmente positivas a la reacción de AB desde los 15 días de edad, pero no a los 5 días de la edad. Las JG y VBG fueron fuertemente positivas a la immunolocalization del AR en las edades estudiadas (15, 25 y 35 días de edad). Las DBG fueron siempre negativas a las reacciones de PAS y AB. El NE, el RFE y el RE fueron negativos. Según nuestro conocimiento, éste es el primer informe de immunolocalization del AR en el VNO y la mucosa del tabique nasal. Los actuales resultados sugieren una influencia de los andrógenos en el mecanismo por el cual entran en contacto las feromonas y el Ne, a través de la regulación por andrógenos de la secreción de las JG.

Electroantennographic responses of the Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva) (Diptera: Psychodidae) to 1-octen-3-ol / Respostas eletroantenográficas de Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva) (Diptera: Psychodidae) a 1-octen-3-ol

Octenol (1-octen-3-ol) é um cairomônio utilizado por vários grupos de insetos hematófagos para a localização de hospedeiros vertebrados. No entanto, o seu efeito sobre Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva) nunca foi estudado. O presente trabalho avaliou as respostas eletroantenográficas (EAG) de fêmeas de L. longipalpis. Como estímulo controle utilizou-se corrente de ar, pulsos de ar e pulsos de solvente (hexano). As concentrações logarítmicas de 1-octen-3-ol testadas foram de 10 a 10(6) etag/50mil de solvente. Observaram-se respostas olfativas significativas de 1-octen-3-ol a partir de 10³etag/50mil, tendo a maior amplitude na concentração 10(6)etag/50mil (-3,33mV). Foi observada dose-dependência, ou seja, quanto maior a concentração, maior foi a resposta eletrofisiológica. Estes resultados demonstram, pela primeira vez que L. longipalpis pode detectar a presença do 1-octen-3-ol em corrente de ar. O possível uso de 1-octen-3-ol como cairomônio é discutido para a espécie.

Octenol (1-octen-3-ol) is a kairomone used by haematophagous insects to locate their vertebrate hosts. However, effect of 1-octen-3-ol on Lutzomyia (Lutzomyia) longipalpis (Lutz & Neiva) has never been studied. The present work evaluated the electrophysiological (EAG) responses of female L. (Lutzomyia) longipalpis. Air current, air pulse and solvent (hexane) pulse were used as control stimuli. The logarithmic concentrations of 1-octen-3-ol 10 a 10(6) etag/50æl of solvent were tested. Significant olfactory responses were observed in the concentration of 1-octen-3-ol from 10³ etag/50ul with the greatest response at concentration of 10(6) etag/50ul (-3,33mV). Dose-dependency was observed, as the concentration increased, so did the electrophysiological response. These results demonstrated, for the first time, that L. longipalpis, can detect the presence of 1-octen-3-ol in air current. The possible use of 1-octen-3-ol as kairomone for this species is discussed.