OBJECTIVE: To study the distribution and metabolism of methamphetamine in the hair of guinea pig. METHODS: Determination of methamphetamine and its metabolite amphetamine in hair was performed by GC/MS and GC/NPD. Concentration-time course of methamphetamine and amphetamine in hair of guinea were recorded. Relationship between hair color, administrated dose and drug concentration in hair were also discussed. RESULTS: The concentration of amphetamine is higher than the concentration of methamphetamine in the hair of guinea administrated a single dose or seven doses of methamphetamine. The concentration of methamphetamine and amphetamine were significantly related with administration dose and the incorporation rate into white and brown hair is much poorer than that of black hair. CONCLUSION Administration methods, dose and the color of hair affect the concentration of methamphetamine and amphetamine.
Amphetamine/metabolism* ; Animals ; Guinea Pigs ; Hair/metabolism* ; Hair Color ; Male ; Methamphetamine/metabolism*

Humans ; Finasteride/pharmacology* ; Dutasteride/pharmacology* ; 5-alpha Reductase Inhibitors/pharmacology* ; Testosterone/metabolism* ; Hair Follicle/metabolism* ; Transcriptome ; Hair/metabolism*

Adult ; Autopsy ; Female ; Hair ; metabolism ; Humans ; Liver ; pathology ; Thallium ; poisoning

Ethyl glucuronide is a specific metabolite of ethanol. There have been plenty of articles referring its pharmacokinetics, detection and application as a specific bio-marker of alcohol intake. This article reviews various analytical methods of EtG, relationship between EtG quantification and ethanol intake, and criteria for determining chronic alcohol abuse, and origin of ethanol found in the cadavers by EtG analysis. EtG has its potential application in forensic toxicology.
Alcoholism/metabolism* ; Forensic Toxicology/methods* ; Glucuronates/urine* ; Hair/chemistry* ; Humans

OBJECTIVE: To investigate the expression of adaptin-2(AP-2) in mice cochlea and to discuss the probable role in the endocytosis of hair cells. METHOD: Laser scanning confocal microscopy and immune-fluroscence histochemistry were performed in this study. RESULT: In mature mice cochlea, the immunoreactivity for AP-2 was found in the inner hair cells cytoplasm. This protein mainly expressed in the hair cells basal part and nearby the ribbon synapse. CONCLUSION AP-2 protein mainly expressed in the hair cells synaptic activity zone , which suggested that AP-2 could play an important role in the synaptic vesicle endocytosis. This finding built the foundation for the further research involved in the physiological and pathological role of AP-2.
Adaptor Protein Complex alpha Subunits ; metabolism ; Animals ; Cochlea ; Hair Cells, Auditory ; Hair Cells, Auditory, Inner ; metabolism ; Mice ; Microscopy, Confocal ; Synapses

OBJECTIVE: To investigate the expression of Myosin VI and Disabled-2 (Dab2) in the cochlea of mice at different ages. METHOD: Forty KM mice were divided into four groups according to age, named as postnatal 2 week (P2w), P5w, P9w, P16month. The localization of protein in the basilar membrane of mice cochlea was detected by immunofluorescence staining and laser scanning confocal microscope (LSCM). The mRNA expression level of protein in cochlear at different ages was evaluated by real-time fluorescent quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Statistical analysis was performed by the SPSS18.0 software. RESULT: Myosin VI and Disabled-2 protein mainly expressed at the apical cytoplasm of hair cells. As for the inner hair cell, Dab2 labeling was abundant especially at the cuticular plate and nearby. Comparing four immunofluorescence staining images of Myosin VI, we found the fluorescence intensity of P2w and P16m were weaker than that of P5w and P9w. After setting P9w as the control group, qRT-PCR revealed that the mRNA expression of MyosinVI and Dab2 in P2w was less than that in the control group (P < 0.01), while no significant difference was found between P5w and the control group, nor between P16m and the control group (P > 0.05). CONCLUSION Myosin VI and Dab2, two proteins which regulated the clathrin-mediated endocytosis, expressed at hair cells of mice cochlea. In the inner hair cell, this process of endocytosis may be more efficient at the cuticular plate and nearby. The expression level of protein may change in different ages, and this probably leads to a difference of CME, it also may cause a defect of inner hair cells function.
Adaptor Proteins, Vesicular Transport ; metabolism ; Aging ; Animals ; Cochlea ; metabolism ; Endocytosis ; Hair Cells, Auditory ; metabolism ; Hair Cells, Auditory, Inner ; metabolism ; Mice ; Microscopy, Confocal ; Myosin Heavy Chains ; metabolism

The cochlear auditory epithelium contains two types of sound receptors, inner hair cells (IHCs) and outer hair cells (OHCs). Mouse models for labelling juvenile and adult IHCs or OHCs exist; however, labelling for embryonic and perinatal IHCs or OHCs are lacking. Here, we generated a new knock-in Fgf8^P2A-3×GFP/+ (Fgf8^GFP/+) strain, in which the expression of a series of three GFP fragments is controlled by endogenous Fgf8 cis-regulatory elements. After confirming that GFP expression accurately reflects the expression of Fgf8, we successfully obtained both embryonic and neonatal IHCs with high purity, highlighting the power of Fgf8^GFP/+. Furthermore, our fate-mapping analysis revealed, unexpectedly, that IHCs are also derived from inner ear progenitors expressing Insm1, which is currently regarded as an OHC marker. Thus, besides serving as a highly favorable tool for sorting early IHCs, Fgf8^GFP/+ will facilitate the isolation of pure early OHCs by excluding IHCs from the entire hair cell pool.
Animals ; Mice ; Hair Cells, Auditory, Inner ; Cochlea/metabolism* ; Hair Cells, Auditory, Outer/metabolism* ; Disease Models, Animal ; Fibroblast Growth Factor 8/metabolism*

Recent studies have revealed great functional and structural heterogeneity in the ribbon-type synapses at the basolateral pole of the isopotential inner hair cell (IHC). This feature is believed to be critical for audition over a wide dynamic range, but whether the spatial gradient of ribbon morphology is fine-tuned in each IHC and how the mitochondrial network is organized to meet local energy demands of synaptic transmission remain unclear. By means of three-dimensional electron microscopy and artificial intelligence-based algorithms, we demonstrated the cell-wide structural quantification of ribbons and mitochondria in mature mid-cochlear IHCs of mice. We found that adjacent IHCs in staggered pairs differ substantially in cell body shape and ribbon morphology gradient as well as mitochondrial organization. Moreover, our analysis argues for a location-specific arrangement of correlated ribbon and mitochondrial function at the basolateral IHC pole.
Animals ; Artificial Intelligence ; Cochlea/metabolism* ; Hair Cells, Auditory, Inner ; Mice ; Mitochondria ; Synapses/metabolism*

OBJECTIVETo investigate the expression of Dynamin subtypes in inner hair cell (IHC) of mice, and to discuss their possible roles in age-related hearing loss.

METHODSAuditory brainstem response (ABR) was recorded from the Kunming mice on postnatal 3 weeks (young), 10 weeks (adult), and 16 months (aged), 10 mice in each group. The expression of each Dynamin isoforms in the hair cells of the cochlea was observed by immunofluorescence staining and confocal microscope, and the transcription level of Dynamin subtypes mRNA was detected in qRT-PCR. Data analysis using SPSS 18 software.

RESULTSABR threshold showed no significant difference between the group of young and adult (t = -5.273, P = 0.076), but the threshold of the aged group increased comparing with young group (t = -8.365, P = 0.000), and adult group (t = -6.191, P = 0.000). All subtypes expressed in the inner hair cell of mice, of which Dynamin-1 and 2 expressed in the whole inner hair cell in the group of young and adult. In the aged group, Dynamin-1 was lost beneath the nucleus, and Dynamin-2 only be found near the nucleus. In addition, Dynamin-3 was scattered in the region of the basal part of the cells beneath the nucleus and near the spiral ganglion. The qRT-PCR revealed that mRNA of Dynamin-1 reduced with age (F = 10.410, P = 0.011), mRNA of Dynamin-2 increased to a peak in the adult group and then reduced with age (F = 24.575, P = 0.000). Meanwhile, mRNA of Dynamin-3 was not be detected.

CONCLUSIONSAll subtypes of Dynamin express in IHC. The expression of Dynamin-1 and 2 is up-regulated during maturity, which might alter the endocytosis of IHC; and the disorder of endocytosis might modulate the synaptic transmission of IHC. Whether Dynamin-3 plays a role in inner hair cells remains unclear because of the low expression.

Aging ; metabolism ; Animals ; Cochlea ; metabolism ; Dynamins ; metabolism ; Evoked Potentials, Auditory, Brain Stem ; Hair Cells, Auditory, Inner ; metabolism ; Mice

In mammals, the piezoelectric protein, Prestin, endows the outer hair cells (OHCs) with electromotility (eM), which confers the capacity to change cellular length in response to alterations in membrane potential. Together with basilar membrane resonance and possible stereociliary motility, Prestin-based OHC eM lays the foundation for enhancing cochlear sensitivity and frequency selectivity. However, it remains debatable whether Prestin contributes to ultrahigh-frequency hearing due to the intrinsic nature of the cell's low-pass features. The low-pass property of mouse OHC eM is based on the finding that eM magnitude dissipates within the frequency bandwidth of human speech. In this study, we examined the role of Prestin in sensing broad-range frequencies (4-80 kHz) in mice that use ultrasonic hearing and vocalization (to >100 kHz) for social communication. The audiometric measurements in mice showed that ablation of Prestin did not abolish hearing at frequencies >40 kHz. Acoustic associative behavior tests confirmed that Prestin-knockout mice can learn ultrahigh-frequency sound-coupled tasks, similar to control mice. Ex vivo cochlear Ca²⁺ imaging experiments demonstrated that without Prestin, the OHCs still exhibit ultrahigh-frequency transduction, which in contrast, can be abolished by a universal cation channel blocker, Gadolinium. In vivo salicylate treatment disrupts hearing at frequencies <40 kHz but not ultrahigh-frequency hearing. By pharmacogenetic manipulation, we showed that specific ablation of the OHCs largely abolished hearing at frequencies >40 kHz. These findings demonstrate that cochlear OHCs are the target cells that support ultrahigh-frequency transduction, which does not require Prestin.
Animals ; Cochlea/metabolism* ; Hair Cells, Auditory, Outer/metabolism* ; Hearing ; Humans ; Mammals/metabolism* ; Mice ; Mice, Knockout ; Molecular Motor Proteins/metabolism*