Hyperosmia is an increase in olfactory olfaction (olfancy), usually caused by a lower threshold for odors. This perceptual disorder arises when there is an abnormally elevated signal at any point between the olfactory receptor and the olfactory cortex. The cause of hyperosmia may be genetic, environmental or the result of benzodiazepine withdrawal syndrome.
When the odors enter the nasal cavity, they bind to the odor receptors at the base of the olfactory epithelium. These receptors are bipolar neurons that connect to the glomerular layer of the olfactory bulbus, running through the cribiform plate. In the glomerular layer, the axons of the olfactory receptor neurons mingle with the dendrites of intrinsic bulb intrinsic bulb: mitrial/tufted cells and dopaminergic periglomerular cells. From the olfactory bulb, the mitral/tufted cells send the axon through the lateral olfactory channel (cranial nerve I) to the olfactory cortex, which includes the piriform cortex, the entorhinal cortex, and the amygdala portions. From the entorhinal cortex, the axon extends to the medial thoracic dorsal nucleus, which then progresses into the orbitofrontal cortex.
Video Hyperosmia
Penyebab genetik
A study by Menashe et al. have found that individuals with a single nucleotide polymorphism variant in ORESH7P pseudogene have a lower receptor activation threshold for isovaleric acid. These people are hyperosmic for this singular smell.
Another study by Keller et al. have found that people with human ORD receptor intact OR7D4 are more sensitive to androstenone and androstadienone and thus find them unpleasant (individuals with semi-functional OR7D4 have two non-identical single nucleotide polymorphisms in pseudogene OR7D4, yielding two amino acid substitutions). There has not been extensive research into their genetic background with general hyperosmia, not just for one smell.
Maps Hyperosmia
Environmental causes
There has been no extensive research on the causes of environmental hyperosmia, but there are several theories about some possible causes.
In a study by Atianjoh et al., It has been found that amphetamine lowers dopamine levels in olfactory bulbs of rodents. On the basis of this, it has been hypothesized that the use of amphetamine may cause hyperosmia in rodents and humans, but further research is still needed. Anecdotal support for the belief that amphetamines can cause hyperosmia stems from Oliver Sacks' notes of patients with increased olfactory after taking amphetamines.
It has been observed that inhaling hydrocarbons can cause hyperosmia, most likely due to destruction of dopaminergic neurons in olfactory bulb.
Methotrexate, given in the treatment of psoriasis, has been known to cause hyperosmia, and may be more likely to do so in patients with a history of migraine. However, this is only observation and not part of the research, therefore it has not been verified.
Treatment
Normal olfactory acuity usually goes back from time to time if the cause is environmental, even if it is not treated. Hyperosmic people may need to be expelled from a strong odor for an extended period of time if the sensation becomes unbearable. Before they are terminated due to unwanted side effects, butyrophenones or thioridazine hydrochloride, both dopamine antagonists, have been used to treat hyperosmia.
See also
- Phantosmia
- Hyposmia
- Multiple chemical sensitivity, a condition believed to be in part due to acute olfaction
- olfaction
- Oliver Sacks
- Benzodiazepine withdrawal syndrome
- Parosmia
References
Source of the article : Wikipedia
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