Mammalian Pheromones
Topic 6: Mammalian Pheromones
Abstract
A pheromone is a chemical signal which is released by one animal and received by another, which induce a species specific reaction. Pheromones are detected via chemosensory systems known as the Vomeronasal Organ (VNO). Within a wide range of mammals the VNO is used to elicit a generalized sexual response, primarily affecting the reproductive tract. This is seen in most terrestrial mammals who have adapted to sensing volatile chemical signals; the Mouse displays the general VNO function. Additionally, some mammalian species have adapted the ability to respond to a variety of pheromonal signals which can alter their physiological behavior. Mice can also respond to chemo-signals from animals within and
outside …show more content…
their species, such as predators. This specialized VNO function can mediate long term physiological responses, in contrast to the main olfactory system (MOS) which mediates short term physiological responses. Furthermore, certain mammalian species display a vestigial VNO in response to environmental adaptations, which is caused by the loss of the
TRPC2 gene responsible for VNO function. Within marine mammals, the function of the VNO is related to their degree of aquatic specialization. Likewise, the loss of a functional VNO has also evolved in certain species of primates due to the reliance on visual and auditory cues for reproductive communication. This presentation explores the various roles of the VNO within different mammalian species, as well as the importance of the TRPC2 gene necessary in VNO function.
Introduction
Signal transduction in the Vomeronasal organ:
Sensory neurons in Vomeronasal Organ
Accessory Olfactory Bulb
Vomeronasal Amydala
The Mammalian Vomeronasal Organ: Beyond Attracting A Mate
The Question
How does the Vomeronasal System compare among various mammals?
What is the significance of the TRPC2 gene in mammals? Mouse:
•How can the rodent vomeronasal system distinguish conspecific and interspecific stimuli?
•What are the physiological responses to conspecific and interspecific stimuli?
Marine Mammals
•What is the relative importance of pheromone signaling in response to aquatic specialization?
Primates
•At what point did the Vomeronasal Organ become vestigial in humans?
Conclusions
The Mouse Story:
Mouse urine: generalized sex response
• regulator of endocrine responses of male, elicits sexual behavioural responses
•Predator urine: when surveying a niche, VNO used as long term modulation of mouse reproductive physiology
•olfactory detection is immediate avoidance of predators Delay of reproduction
Mouse and predator urine: have overlapping components on AOB, combination elicits robust response, so predator cue does not over ride others
•AOB cells integrate information from multiple glomeruli The Marine Story:
•Adaptations to water cause decreased dependence on pheromone signaling
•Cetaceans and River Otter do not have VNS
•All Pinnipeds have a VNS except Harbor Seal
•Transgenic Mice
•Anesthetised rats
•Fluorescence dye in stimuli to trace the uptake path combined with sympathetic stimulation to evoke a neural response in AOB
•exploratory behaviours
•Multi site electrodes record how AOB neurons respond to conspecific and interspecific saliva and urine
The Marine Story:
•4 species with varying degrees of aquatic adaptation
•Completely aquatic cetacean (Fin Whale)
•Semi-aquatic (River Otter)
•Amphibious Pinnipeds (California Sea Lion & Harbor
Seal)
•ORF sequence of 22 exons in TRPC2 gene
•Control: Dog, Cow and Mouse
•Molecular Ratios to analyze selective pressure of gene
•Phylogenetic Analysis to asses lineages
•Molecular data bases
•Control: Mice TRPC2 gene
•PCR Amplification and Sequencing of Primate DNA in 15 species •Phylogenetic Analysis to assess lineages
Results
The Mouse Story:
•Mouse urine- detection of species, gender in varying quantities and concentrations
•Doesn’t exhibit flehemen behaviour
•Predator urines- bobcat or fox urine evoke robust responses in all the mice
•AOB neurons magnitude and frequency large
•specific in distinct predator species
•Conflicting Stimuli-Mixes of predator and female mouse urine worked synergistically in AOB
Figure 2.0: Charts illustrating the response frequency and strength of conspecific and interspecific stimuli.
The Marine Story:
Now What?
The Mouse Story:
•Explore combinatory stimuli further
•Predators, overmarking
•Explore the chemical composition of predator urine: pest control Issues
•Complex chemical composition of stimuli
•Difficult to track volatile stimuli upon reaching brain
Figure 3.0: Phylogenetic Tree displaying the independent evolution of the
TRPC2 gene in marine mammals due to relaxed selective pressures
The Primate Story:
The Marine Story:
•Pheromone olfaction in marine mammals is complex:
•Study more VNS specific genes/TRPC2 gene
•Study wider range of marine mammals from different lineages The Primate Story:
•Future studies for the possibility of a VNO in humans
•Small pit retained in nasal septum but cells in presumptive VNS do not express markers of mature sensory neurons
•No evident accessory olfactory bulb
Figure 1.0 Olfactory system rodent s displaying pheromonal transduction pathway
•Vomeronasal System specific gene
•sensory microvilli of VNO
•Expression/function necessary for pheromone response •Pseudogenized TRPC2 gene impairs signal transduction • Certain primate species (ie.humans)
•Used as molecular marker to study function of the VNO in species across evolution
The Mouse Story:
The Primate Story:
Specific Nuclei in the Hypothalamus
TRPC2 Gene
Methods
Figure 4.0: Phylogenetic Tree displaying evolution of TRPC2 gene in primates due to relaxed selective pressures.
References
Ben-Shaul, Y., Katz, L. C., Mooney, R., & Dulac, C. (2010). In vivo vomeronasal stimulation reveals sensory encoding of conspecific and allospecific cues by the mouse accessory olfactory bulb. PNAS, 107(11), 5172-5177.
Fahlike, J., Gingerich, P., Welsh, R., & Wood, A. (2011). Cranial asymmetry in eocene archaeocete whales and the evolution of directional hearing in water.PNAS, 108(35), 14545-14548. Retrieved from http://www.pnas.org/search?fulltext=whale anatomy&submit=yes&x=0&y=0 He J., Ma L., Kim S.S., Nakai J., Yu C.R. (2008) Encoding Gender and Individual Information in the Mouse Vomeronasal Organ.
Science. 320 pp 535-538 Schneider N.Y., Fletcher T.P., Shaw G., Renfree M. B. (2008) The vomeronasal organ of the tammar wallaby. Journal of Anatomy. 213 pp 93-105
He J., Ma L., Kim S.S., Schwartz J., Santilli M., Wood C., Durnin M.H., Yu C.R. (2010) Distinct Signals Conveyed by Pheromone
Concentrations to the Mouse Vomeronasal Organ. The Journal of Neuroscienc. 30(22) pp 7473-7483
Figure 4.0: Anatomy of Cetacean displaying various pheromone adaptations Kylokawa, Y., Kodama, Y., Kubota, T., Takechu, Y., Takechu, Y., & Mori, Y. (2013). Alarm pheromone is detected by the
vomeronasal organ in male rats. Oxford Journal, 38, 661-668.
Liman, E., & Innan, H. (2003). Relaxed selective pressure on an essential component of pheromone transduction in primate evolution. PNAS, 100(6), 3328-3332. Retrieved from http://www.pnas.org/content/100/6/3328.short.
The Primate Story:
•VNO became vestigial among primates in common ancestor of OW monkeys and Apes
•Trichromatic colour vision & signal via skin pigmentation •NW monkeys show scent marking behavior; communication not through VNO (Only Lemurs retain functional VNO)
Lledo, P., Gheusi, G., & Vincent, J. (2005). Information processing in the mammalian olfactory system.American Physiological
Society , 85, 281-317. Retrieved from http://physrev.physiology.org/content/85/1/281
Pageat, P., & Gaultier, E. (2003). Current research in canine and feline pheromones. Elsevier Science, 33(2003), 187-211.
Schneider N.Y., Fletcher T.P., Shaw G., Renfree M. B. (2008) The vomeronasal organ of the tammar wallaby. Journal of Anatomy.
213 pp 93-105
Takigami, S., Mori, Y., Tanioka, Y., & Ichikawa, M. (2004). Morphological evidence for two types of mammalian vomeronasal system. Oxford Journal, 29, 301-310.
Figure 5.0: Anatomy of mammalian VNO
Yu, L., Jin, W., Wang, J., Zhang, X., Chen, M., Zhu, Z., Lee, H., & Lee, M. (2010). Characterization of trpc2, an essential genetic component of vns chemoreception, provides insights into the evolution of pheromonal olfaction in secondary-adapted marine mammals. Molecular Biology Evolution,27(7), 1467-1477. Retrieved from
http://www.ncbi.nlm.nih.gov/pubmed/20142439
Abstract
A pheromone is a chemical signal which is released by one animal and received by another, which induce a species specific reaction. Pheromones are detected via chemosensory systems known as the Vomeronasal Organ (VNO). Within a wide range of mammals the VNO is used to elicit a generalized sexual response, primarily affecting the reproductive tract. This is seen in most terrestrial mammals who have adapted to sensing volatile chemical signals; the Mouse displays the general VNO function. Additionally, some mammalian species have adapted the ability to respond to a variety of pheromonal signals which can alter their physiological behavior. Mice can also respond to chemo-signals from animals within and
outside …show more content…
their species, such as predators. This specialized VNO function can mediate long term physiological responses, in contrast to the main olfactory system (MOS) which mediates short term physiological responses. Furthermore, certain mammalian species display a vestigial VNO in response to environmental adaptations, which is caused by the loss of the
TRPC2 gene responsible for VNO function. Within marine mammals, the function of the VNO is related to their degree of aquatic specialization. Likewise, the loss of a functional VNO has also evolved in certain species of primates due to the reliance on visual and auditory cues for reproductive communication. This presentation explores the various roles of the VNO within different mammalian species, as well as the importance of the TRPC2 gene necessary in VNO function.
Introduction
Signal transduction in the Vomeronasal organ:
Sensory neurons in Vomeronasal Organ
Accessory Olfactory Bulb
Vomeronasal Amydala
The Mammalian Vomeronasal Organ: Beyond Attracting A Mate
The Question
How does the Vomeronasal System compare among various mammals?
What is the significance of the TRPC2 gene in mammals? Mouse:
•How can the rodent vomeronasal system distinguish conspecific and interspecific stimuli?
•What are the physiological responses to conspecific and interspecific stimuli?
Marine Mammals
•What is the relative importance of pheromone signaling in response to aquatic specialization?
Primates
•At what point did the Vomeronasal Organ become vestigial in humans?
Conclusions
The Mouse Story:
Mouse urine: generalized sex response
• regulator of endocrine responses of male, elicits sexual behavioural responses
•Predator urine: when surveying a niche, VNO used as long term modulation of mouse reproductive physiology
•olfactory detection is immediate avoidance of predators Delay of reproduction
Mouse and predator urine: have overlapping components on AOB, combination elicits robust response, so predator cue does not over ride others
•AOB cells integrate information from multiple glomeruli The Marine Story:
•Adaptations to water cause decreased dependence on pheromone signaling
•Cetaceans and River Otter do not have VNS
•All Pinnipeds have a VNS except Harbor Seal
•Transgenic Mice
•Anesthetised rats
•Fluorescence dye in stimuli to trace the uptake path combined with sympathetic stimulation to evoke a neural response in AOB
•exploratory behaviours
•Multi site electrodes record how AOB neurons respond to conspecific and interspecific saliva and urine
The Marine Story:
•4 species with varying degrees of aquatic adaptation
•Completely aquatic cetacean (Fin Whale)
•Semi-aquatic (River Otter)
•Amphibious Pinnipeds (California Sea Lion & Harbor
Seal)
•ORF sequence of 22 exons in TRPC2 gene
•Control: Dog, Cow and Mouse
•Molecular Ratios to analyze selective pressure of gene
•Phylogenetic Analysis to asses lineages
•Molecular data bases
•Control: Mice TRPC2 gene
•PCR Amplification and Sequencing of Primate DNA in 15 species •Phylogenetic Analysis to assess lineages
Results
The Mouse Story:
•Mouse urine- detection of species, gender in varying quantities and concentrations
•Doesn’t exhibit flehemen behaviour
•Predator urines- bobcat or fox urine evoke robust responses in all the mice
•AOB neurons magnitude and frequency large
•specific in distinct predator species
•Conflicting Stimuli-Mixes of predator and female mouse urine worked synergistically in AOB
Figure 2.0: Charts illustrating the response frequency and strength of conspecific and interspecific stimuli.
The Marine Story:
Now What?
The Mouse Story:
•Explore combinatory stimuli further
•Predators, overmarking
•Explore the chemical composition of predator urine: pest control Issues
•Complex chemical composition of stimuli
•Difficult to track volatile stimuli upon reaching brain
Figure 3.0: Phylogenetic Tree displaying the independent evolution of the
TRPC2 gene in marine mammals due to relaxed selective pressures
The Primate Story:
The Marine Story:
•Pheromone olfaction in marine mammals is complex:
•Study more VNS specific genes/TRPC2 gene
•Study wider range of marine mammals from different lineages The Primate Story:
•Future studies for the possibility of a VNO in humans
•Small pit retained in nasal septum but cells in presumptive VNS do not express markers of mature sensory neurons
•No evident accessory olfactory bulb
Figure 1.0 Olfactory system rodent s displaying pheromonal transduction pathway
•Vomeronasal System specific gene
•sensory microvilli of VNO
•Expression/function necessary for pheromone response •Pseudogenized TRPC2 gene impairs signal transduction • Certain primate species (ie.humans)
•Used as molecular marker to study function of the VNO in species across evolution
The Mouse Story:
The Primate Story:
Specific Nuclei in the Hypothalamus
TRPC2 Gene
Methods
Figure 4.0: Phylogenetic Tree displaying evolution of TRPC2 gene in primates due to relaxed selective pressures.
References
Ben-Shaul, Y., Katz, L. C., Mooney, R., & Dulac, C. (2010). In vivo vomeronasal stimulation reveals sensory encoding of conspecific and allospecific cues by the mouse accessory olfactory bulb. PNAS, 107(11), 5172-5177.
Fahlike, J., Gingerich, P., Welsh, R., & Wood, A. (2011). Cranial asymmetry in eocene archaeocete whales and the evolution of directional hearing in water.PNAS, 108(35), 14545-14548. Retrieved from http://www.pnas.org/search?fulltext=whale anatomy&submit=yes&x=0&y=0 He J., Ma L., Kim S.S., Nakai J., Yu C.R. (2008) Encoding Gender and Individual Information in the Mouse Vomeronasal Organ.
Science. 320 pp 535-538 Schneider N.Y., Fletcher T.P., Shaw G., Renfree M. B. (2008) The vomeronasal organ of the tammar wallaby. Journal of Anatomy. 213 pp 93-105
He J., Ma L., Kim S.S., Schwartz J., Santilli M., Wood C., Durnin M.H., Yu C.R. (2010) Distinct Signals Conveyed by Pheromone
Concentrations to the Mouse Vomeronasal Organ. The Journal of Neuroscienc. 30(22) pp 7473-7483
Figure 4.0: Anatomy of Cetacean displaying various pheromone adaptations Kylokawa, Y., Kodama, Y., Kubota, T., Takechu, Y., Takechu, Y., & Mori, Y. (2013). Alarm pheromone is detected by the
vomeronasal organ in male rats. Oxford Journal, 38, 661-668.
Liman, E., & Innan, H. (2003). Relaxed selective pressure on an essential component of pheromone transduction in primate evolution. PNAS, 100(6), 3328-3332. Retrieved from http://www.pnas.org/content/100/6/3328.short.
The Primate Story:
•VNO became vestigial among primates in common ancestor of OW monkeys and Apes
•Trichromatic colour vision & signal via skin pigmentation •NW monkeys show scent marking behavior; communication not through VNO (Only Lemurs retain functional VNO)
Lledo, P., Gheusi, G., & Vincent, J. (2005). Information processing in the mammalian olfactory system.American Physiological
Society , 85, 281-317. Retrieved from http://physrev.physiology.org/content/85/1/281
Pageat, P., & Gaultier, E. (2003). Current research in canine and feline pheromones. Elsevier Science, 33(2003), 187-211.
Schneider N.Y., Fletcher T.P., Shaw G., Renfree M. B. (2008) The vomeronasal organ of the tammar wallaby. Journal of Anatomy.
213 pp 93-105
Takigami, S., Mori, Y., Tanioka, Y., & Ichikawa, M. (2004). Morphological evidence for two types of mammalian vomeronasal system. Oxford Journal, 29, 301-310.
Figure 5.0: Anatomy of mammalian VNO
Yu, L., Jin, W., Wang, J., Zhang, X., Chen, M., Zhu, Z., Lee, H., & Lee, M. (2010). Characterization of trpc2, an essential genetic component of vns chemoreception, provides insights into the evolution of pheromonal olfaction in secondary-adapted marine mammals. Molecular Biology Evolution,27(7), 1467-1477. Retrieved from
http://www.ncbi.nlm.nih.gov/pubmed/20142439