RESUMO

OBJECTIVES: The new corona virus infection, has a wide range of clinical manifestations. Fever and cough are the most common symptoms. The olfactory function may be also affected with COVID-19. In this randomized clinical trial, we wanted to evaluate the therapeutic effect of olfactory training with and without oral vitamin A for COVID-19-related olfactory dysfunction. METHODS: Patients answered to the standard Persian version of anosmia reporting tool and performed the quick smell test before and after 12 weeks and at the end of the 12 months follow up. The patients were randomly allocated to three groups; Group A treatment with olfactory training, Group B treatment with oral vitamin A and olfactory training, and Group C as control group which only underwent nasal irrigation twice a day. Patients were treated for 3 months and followed up for 12 months. RESULTS: Totally 90 patients were included in three groups. After interventions, 76.9% of patients in Group A, 86.7% of patients in Group B, and 26.7% of patients in Group C completely improved. The average intervention time was statistically significant in relationship with the final olfactory status of the patients in the 12 months follow-up. The olfactory training has significantly improved the smell alteration at the end of 3- and 12- months follow-up in A and B groups. CONCLUSION: A three-months olfactory training is effective for improvement of COVID-19-related olfactory dysfunction. Adding daily oral vitamin A to olfactory training did not lead to better results in improving olfactory dysfunction. LEVEL OF EVIDENCE: Step 2 (Level 2*): Randomized trial.

Assuntos

COVID-19 , Transtornos do Olfato , Vitamina A , Humanos , Vitamina A/uso terapêutico , Vitamina A/administração & dosagem , COVID-19/complicações , Masculino , Feminino , Método Duplo-Cego , Transtornos do Olfato/etiologia , Transtornos do Olfato/tratamento farmacológico , Pessoa de Meia-Idade , Adulto , Resultado do Tratamento , Vitaminas/uso terapêutico , Vitaminas/administração & dosagem , Treinamento Olfativo

RESUMO

Melatonin MT1 and MT2 receptors are expressed in the glomerular layer of the olfactory bulb (OB); however, the role of these receptors has not been evaluated until now. Considering the association of the OB with olfactory and depressive disorders in Parkinson's disease (PD), we sought to investigate the involvement of melatonin receptors in these non-motor disturbances in an intranigral 6-hydroxydopamine (6-OHDA)-lesioned rat model of PD. We demonstrate the presence of functional melatonin receptors in dopaminergic neurons of the glomerular layer. Local administration of melatonin (MLT, 1 µg/µl), luzindole (LUZ, 5 µg/µl) or the MT2-selective receptor drug 4-P-PDOT (5 µg/µl) reversed the depressive-like behavior elicited by 6-OHDA. Sequential administration of 4-P-PDOT and MLT (5 µg/µl, 1 µg/µl) promoted additive antidepressant-like effects. In the evaluation of olfactory discrimination, LUZ induced an olfactory impairment when associated with the nigral lesion-induced impairment. Thus, our results suggest that melatonin MT2 receptors expressed in the glomerular layer are involved in depressive-like behaviors and in olfactory function associated with PD.

Assuntos

Anosmia/metabolismo , Comportamento Animal , Transtorno Depressivo/metabolismo , Neurônios Dopaminérgicos/metabolismo , Bulbo Olfatório/metabolismo , Transtornos Parkinsonianos/metabolismo , Receptor MT2 de Melatonina/metabolismo , Animais , Anosmia/etiologia , Anosmia/fisiopatologia , Anosmia/psicologia , Comportamento Animal/efeitos dos fármacos , Transtorno Depressivo/etiologia , Transtorno Depressivo/fisiopatologia , Transtorno Depressivo/psicologia , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Locomoção/efeitos dos fármacos , Masculino , Melatonina/farmacologia , Bulbo Olfatório/efeitos dos fármacos , Bulbo Olfatório/fisiopatologia , Percepção Olfatória/efeitos dos fármacos , Oxidopamina , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/fisiopatologia , Transtornos Parkinsonianos/psicologia , Ratos Wistar , Receptor MT2 de Melatonina/efeitos dos fármacos , Transdução de Sinais , Olfato/efeitos dos fármacos , Natação , Tetra-Hidronaftalenos/farmacologia , Triptaminas/farmacologia

RESUMO

The sense of smell allows animals to discriminate a large number of volatile environmental chemicals. Such chemical signaling modulates the behavior of several species that depend on odorant compounds to locate food, recognize territory, predators, and toxic compounds. Olfaction also plays a role in mate choice, mother-infant recognition, and social interaction among members of a group. A key assay to assess the ability to smell odorants is the buried food-seeking test, which checks whether the food-deprived mice can find the food pellet hidden beneath the bedding in the animal's cage. The main parameter observed in this test is the latency to uncover a small piece of chow, cookie, or other pleasant food, hidden beneath a layer of cage bedding, within a limited amount of time. It is understood that food-restricted mice which fail to use odor cues to locate food within a given time period are likely to have deficits in olfactory abilities. Investigators who used the buried food test, or versions of the buried food test, demonstrated that it is possible to evaluate olfactory deficits in different models of murine studies (Alberts and Galef, 1971; Belluscio et al., 1998 ; Luo et al., 2002 ; Li et al., 2013 ). We have recently used this assay to demonstrate that olfactory-specific Ric-8B knock-out mice (a guanine nucleotide exchange factor that interacts with olfactory-specific G-protein) show an impaired sense of smell ( Machado et al., 2017 ). Here we describe the protocol of the buried food-seeking test, as adopted in our assays.