main olfactory receptor
Acronym:
OLRm
The term main olfactory receptor (OLRm) refers to one of two kinds of olfactory receptor (OLR). The other is the accessory olfactory receptor (OLRa). The OLRm is more numerous and its oderant-sensitive dendritic fibers are located in the olfactory epithelium (OLE) that lines the underside of the cribriform plate, the thin bony structure that separates the nasal cavity below from the cranial cavity above. OLRm cell bodies are located on the floor of the cranial cavity above the plate and their axons project via the terminal nerve (tn) to the main olfactory bulb (OLBm).
OLRm's are found in the human ( Buck-2013 ), macaque ( Price-1990 ) and rat and mouse ( Barral-2009 ). They differ from OLRa's in that, whereas OLRa's respond solely to 'social' oderants secreted by other members of the same species and not consciously perceived by humans, OLRm's respond to most oderants that humans sense consciously ( Grammer-2005 ) including both such pleasant aromas as of fresh food, flowers and perfume and unpleasant odors of decaying vegetable matter, putrifying meat and excretory waste.
OLR variants are randomly distributed within overlapping zones of the olfactory epithelium, each of which contains variants sensitive to a range of structurally similar oderant molecutes. The ensemble of randomly distributed neurons of a given variant project to a clustered ensemble of that variant in a spatially clustered ensemble in the olfactory bulb ( Menini-2004 ).
The;physiological function of olfactory receptors is to transduce the chemical signals of unique oderant molecules into electrochemical signals for neural processing and transmission through the olfactory system (OLS). In the human, the total number of olfactory receptor neurons on the two sides of the nose is ~10,000,000 ( Wikipedia ).The number of receptor variants in humans is approximately 350 ( Buck-2013 ). The maximal number of possible combinations and permutations of 350 oderant variants (350-squared) is 122,500... more than enough to account for the human ability to detect ~5,000 to10,000 complex smells. The odor one perceives consciously is associated with the simultaneous excitation of cortical neurons that receive input from the unique combination of oderant receptors activated by volitile molecules emanating from the stimulus ( Buck-2013 ).
Also known as: No other name for this structure has appeared in PubMed.NeuroNames ID : 5717
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