Smell Intensity Monitoring Using Metal Oxide Semiconductor Odor Sensors during Intravenous Olfaction Test

Abstract

The intravenous olfaction test using prosultiamine (PST) solution is simple to perform and has been used clinically in Japan. We monitored intranasal intensity of smell continuously in real time under various conditions of administration using metal oxide semiconductor odor sensors and established an optimal PST injection procedure. In this study, we found that 1) although there was fluctuation in the pattern of intensity of increase in smell in the PST original solution test, the pattern of increase in intranasal smell intensity could be stabilized by prolonging the injection time to 40 s and 2) dilution of PST with physiological saline was effective in preventing angialgia during intravenous injection. It appears that PST administration is best performed by adding 10 ml of saline to 10 mg (2 ml) of PST and injecting the resulting 12-ml solution (6x dilution) and that the best respiratory cycle for testing is once in every 2 s.

Thiazoline-related TRPA1 agonist odorants orchestrate survival fate in mice

“…To examine this possibility, we simultaneously administered lipopolysaccharide (LPS) and 2MT, following which we analyzed the levels of both inflammatory and anti-inflammatory cytokines in the serum. Both vaporized odor presentation and IP injection of odorant molecules are known to activate sensory neurons (Kikuta et al, 2016;Nakashima et al, 2006). Similarly, IP injection of tFOs induced innate fear-related behavioral and physiological responses ( Figure S4K-N).…”

Longer latency of sensory response to intravenous odor injection predicts olfactory neural disorder

“…Previous reports indicate that when PST is intravenously administered to humans, concentration of mercaptan (metabolites of PST) in expired air rapidly increases to a peak within approximately 60 s before gradually decreasing 22 29 . An ascending portion of the odorant concentration curve could regulate onset latency of OSN responses, whereas a descending portion could regulate termination time.…”

“…Orthonasal tests are the most popular. These tests involve OSN stimulation by sniffing odors through the orthonasal pathway 10 11 12 13 14 15 16 17 18 19 20 21 22 . Alternatively, in retronasal tests, OSNs are stimulated through the retronasal pathway ( Fig.…”

“…Alternatively, in retronasal tests, OSNs are stimulated through the retronasal pathway ( Fig. 1a ) 22 23 24 25 26 27 . In the intravenous olfactory (IVO) test, which is considered a retronasal olfactory test, OSNs are stimulated by the intravenously administered odorant prosultiamine (PST).…”

“…1b ) 22 27 28 , but has received substantially less attention from sensory physiologists than orthonasal olfactory tests. However, it is advantageous compared to orthonasal tests because intravenously administered odors are instantaneously and abundantly released into a relatively enclosed cavity within the respiratory tract (nose, trachea, and alveolus), resulting in stronger OSN stimulation compared with that in orthonasal tests 22 29 . Two parameters of the response in the IVO test, latency of odor recognition onset from the time of PST injection and duration between odor recognition onset and disappearance, are measured to determine olfactory loss ( Fig.…”