David (dhe at eden.rutgers.edu) wrote:
: Yes, humans have vomeronasal organs (organs with pheromone receptors),
The terms vomeronasal organ and Jacobson's organ have been used
interchangeably; however, the homology has yet to be demonstrated.
Jacobson is credited with discovering a pit in the human nose that resides
in the epithelium that lines the nasal septum, bilaterally. Hence, the
term Jacobson's organ, which is suitable for whatever Jacobson discovered.
Other investigators, studying other species (notable among them are
reptilies) began to use the term Jacobson's Organ to describe the
vomeronasal organ (which they clearly have). Throughout many decades of
comparative research, it became clear that some amphibians, most reptiles,
and most mammals have a vomeronasal organ (birds lack this structure -- it
is present during embryogenesis but dissappears). The problems began to
arise when descriptions of primates became available. There is no
question that New World primates have a fully developed vomeronasal organ.
Where it has been investigated, prosimians also have a vomeronasal organ.
Whether Old World primates possess a vomeronasal organ (and hence an
accessory olfactory system in general) remains wide open for discussion.
One can find as many references to support the argument that, as adults,
Old World primates lack a vomeronasal organ as references that support the
claim that they have a vomeronasal organ (see Wysocki, C.J. [1979]
Neurobehavioral evidence for the involvment of the vomeronasal system in
mammalian reproduction. Neuroscience and Biobehavioral Reviews, 3,
301-341). If Old World primates have a vomeronasal organ, then it is
*possible* that humans also have a vomeronasal organ. If Old World
primates lack a vomeronasal organ and a vomeronasal system one would be
hard pressed to generate an argument that this structure re-emerged with
the advent of homo sapiens. If the former, then Jacobson's Organ *may* be
homologous with the vomeronasal organ, but there is much comparative work
to be done to demonstrate this. If the latter, then humans possess a
Jacobson's Organ (whatever it is) and others using this term to describe
the vomeronasal organ of other species should drop the term.
: which project to the accessory olfactory bulbs, just as in other
: animals whose behavior is known to be affected by pheromones. In one
It is true that the bipolar receptor cells of animals that have a well
defined vomeronasal organ project to the accessory olfactory bulb. This
has *NOT* been demonstrated for humans or for any other Old World primate.
As a side issue, the term accessory olfactory is a misnomer. In many
instances, the accessory olfactory system, with its receptors in the
vomeronasal organ, is *primary,* i.e., it is the system that is critical
in response to some chemical signals, especially those that affect the
reproductive axis and reproductive behavior.
: experiment, activation of the human vomeronasal organ with certain
: chemosensory cues was shown to induce autonomic responses, which
: differed between men and women. Most subjects could not consciously
Electrical responses, equivalent to ggenerator potentials, were recorded
from Jacobson's organ. One should be cautious in interpreting the orgin
of these responses. Furthermore, it is possible to generate autonomic
responses from activation of free nerve endings of the trigeminal nerve,
which innervates the vomeronasal organ. As for the reported sexual
dimorphism -- there could be numerous reasons, including differences in
the mucus layer.
Another *big* question that remains unanswered is whether Jacobson's Organ
has a neural connection with the brain that is like that seen in other
species that possess a functional vomeronasal organ. In the later, there
exist bipolar receptor cells whose dendrites possess putative pheromone
receptors (to my knowledge, *none* of these have yet been cloned, although
there are numerous reports of cloned putative olfactory receptors, e.g.,
Benarie, N., Lancet, D., Taylor, C., Khen, M., Walker, N., Ledbetter,
D.H., Carrozzo, R., Patel, K., Sheer, D., Lehrach, H. and North, M.A.
Olfactory receptor gene cluster on human chromosome 17 - possible
duplication of an ancestral receptor repertoire. Hum.Mol.Genet. 3:229-235,
1994.
Buck, L. Identification and Analysis of a Multigene Family Encoding
Odorant Receptors - Implications for Mechanisms Underlying Olfactory
Information Processing. Chem.Senses 18:203-208, 1993.
Buck, L. and Axel, R. A Novel Multigene Family May Encode Odorant
Receptors - A Molecular Basis for Odor Recognition. Cell 65:175-187, 1991.
Buck, L.B. Receptor diversity and spatial patterning in the mammalian
olfactory system. Molecular Basis.of Smell.and Taste.Transduction.179.
1993.
Chess, A., Buck, L., Dowling, M.M., Axel, R. and Ngai, J. Molecular
biology of smell - expression of the multigene family encoding putative
odorant receptors. Cold Spring Harb.Symp.Quant.Biol. 57505-516:1992.
Lancet, D., Benarie, N., Cohen, S., Gat, U., Grossisseroff, R., Hornsaban,
S., Khen, M., Lehrach, H., Natochin, M., North, M., Seidemann, E. and
Walker, N. Olfactory receptors - transduction, diversity, human
psychophysics and genome analysis. Molecular Basis.of Smell.and
Taste.Transduction.179. 1993.
Lancet, D., Grossisseroff, R., Margalit, T., Seidemann, E. and Benarie, N.
Olfaction - From Signal Transduction and Termination to Human Genome
Mapping. Chem.Senses 18:217-225, 1993.
Margalit, T. and Lancet, D. Expression of Olfactory Receptor and
Transduction Genes During Rat Development. Brain Res Dev.Brain Res
73:7-16, 1993.
Ngai, J., Dowling, M.M., Buck, L., Axel, R. and Chess, A. The Family of
Genes Encoding Odorant Receptors in the Channel Catfish. Cell 72:657-666,
1993.
Ressler, K.J., Sullivan, S.L. and Buck, L.B. A zonal organization of
odorant receptor gene expression in the olfactory epithelium. Cell
73:597-609, 1993.
Parmentier, M., Libert, F., Schurmans, S., Schiffmann, S., Lefort, A.,
Eggerickx, D., Ledent, C., Mollereau, C., Gerard, C., Perret, J.,
Grootegoed, A. and Vassart, G. Expression of Members of the Putative
Olfactory Receptor Gene Family in Mammalian Germ Cells. Nature
355:453-455, 1992.
Schurmans, S., Muscatelli, F., Miot, F., Mattei, M.G., Vassart, G. and
Parmentier, M. The OLFR1 gene encoding the HGMP07e putative olfactory
receptor maps to the 17p13->p12 region of the human genome and reveals an
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63:200-204, 1993.
Vanderhaeghen, P., Schurmans, S., Vassart, G. and Parmentier, M. Olfactory
receptors are displayed on dog mature sperm cells. J Cell Biol.
123:1441-1452, 1993).
Back to the bipolar receptor cell in the vomeronasal organ -- the cell
bodies of the bipolar cells are located along the medial wall of a lumen
within the vomeronasal organ (bilaterally). The axons of these cells exit
the vomeronasal organ and traverse the nasal septum, cross the cribriform
plate, bypass the main olfactory bulbs and synapse in the accessory
olfactory bulbs. It is these bipolar cells that many claim are lacking in
the human. There are two recent papers that address this issue. The
first,
Takami, S., Getchell, M.L., Chen, Y., Montibloch, L., Berliner, D.L.,
Stensaas, L.J. and Getchell, T.V. Vomeronasal epithelial cells of the
adult human express neuron- specific molecules. Neuroreport. 4:375-378,
1993.
purports to have found a few cells that have a bipolar appearance. The
cells did stain for some epitopes that are associated with neurons, but
the epitopes also are found on neuroendocrine cells. Importantly, the
cells did not stain for olfactory marker protein, which does react with
bipolar cells in other species that have been investigated.
The second
Boehm, N. and Gasser, B. Sensory receptor-like cells in the human foetal
vomeronasal organ. Neuroreport. 4:867-870, 1993.
reports the presence of bipolar cells in the early stages of fetal
development; however, staining is not found in the oldest sample,
suggesting that a vomeronasal epithelium is present during embryonic
development but regresses.
: smell the chemosensory cues. This is evidence suggesting that humans
: respond to the presence of pheromones.
There is considerable evidence to suggest that humans *might* respond to
chemical cues that are not detected as a smell or that the responses are
involuntary. Some of the most recent are those that address some of the
points raised by other contributors to this thread. They include:
Schank, J.C. and McClintock, M.K. A Coupled-Oscillator Model of
Ovarian-Cycle Synchrony Among Female Rats. J Theor.Biol. 157:317-362,
1992.
Weller, A. and Weller, L. Menstrual Synchrony Between Mothers and
Daughters and Between Roommates. Physiol.Behav. 53:943-949, 1993.
Weller, A. and Weller, L. The impact of social interaction factors on
menstrual synchrony in the workplace. Psychoneuroendocrinology. 20:21-31,
1995.
Weller, L. and Weller, A. Human menstrual synchrony - a critical assessment.
Neurosci. Biobehav. Rev. 17:427-439, 1993.
and the earlier work referenced therein.
=========================================================================
Charles J. Wysocki, Ph.D. wysocki at udcemail.udc.upenn.edu
Monell Chemical Senses Center FAX: 215-898-2084
3500 Market Street Phone: 215-898-4265
Philadelphia, PA 19104-3308 telex: 7106700328
