The irritant receptor TRPA1 mediates the mosquito repellent effect of catnip

Melo, Nadia; Capek, Matthew; Arenas, Oscar M.; Afify, Ali; Yilmaz, Ayse Selen; Potter, C. J.; Laminette, Peter J.; Para, Alessia; Gallio, Marco; Stensmyr, Marcus C.

doi:10.1016/j.cub.2021.02.010

Cited by 37 publications

(31 citation statements)

References 46 publications

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“…In this study, we provide experimental evidence for a new mechanism of spatial repellency via activation of sodium channels, independently of activation or inhibition of ORNs, as a principal mechanism of transfluthrin repellency. Together with recent demonstration of activation of a transient receptor potential cation channel (TrpA1) by nepetalactone as a basis of insect repellency [ 47 ], our study provides compelling evidence for an emerging mechanism of insect repellency via activation of insect ion channels other than Orco/Ors. Moreover, our discovery of potential synergism between sodium channel activating transfluthrin and Or-activating DEET points to an exciting possibility to use natural pyrethrins, synthetic pyrethroids or other sodium channel activators as general synergists to increase the potency of DEET and possibly other Or-activating insect repellents.…”

Section: Discussionsupporting

confidence: 71%

Sodium channel activation underlies transfluthrin repellency in Aedes aegypti

et al. 2021

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Background Volatile pyrethroid insecticides, such as transfluthrin, have received increasing attention for their potent repellent activities in recent years for controlling human disease vectors. It has been long understood that pyrethroids kill insects by promoting activation and inhibiting inactivation of voltage-gated sodium channels. However, the mechanism of pyrethroid repellency remains poorly understood and controversial. Methodology/Principal findings Here, we show that transfluthrin repels Aedes aegypti in a hand-in-cage assay at nonlethal concentrations as low as 1 ppm. Contrary to a previous report, transfluthrin does not elicit any electroantennogram (EAG) responses, indicating that it does not activate olfactory receptor neurons (ORNs). The 1S-cis isomer of transfluthrin, which does not activate sodium channels, does not elicit repellency. Mutations in the sodium channel gene that reduce the potency of transfluthrin on sodium channels decrease transfluthrin repellency but do not affect repellency by DEET. Furthermore, transfluthrin enhances DEET repellency. Conclusions/Significance These results provide a surprising example that sodium channel activation alone is sufficient to potently repel mosquitoes. Our findings of sodium channel activation as the principal mechanism of transfluthrin repellency and potentiation of DEET repellency have broad implications in future development of a new generation of dual-target repellent formulations to more effectively repel a variety of human disease vectors.

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Section: Discussionsupporting

confidence: 71%

Sodium channel activation underlies transfluthrin repellency in Aedes aegypti

et al. 2021

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“…S11 ), which hence would also contribute to the avoidance behaviors to camphor. The ion channel TRPA1 and its variants have also been suggested to be involved in insect sensing of natural repellents ( 22 , 34 – 37 ). Our current data show that the trpa1 1 mutant flies showed only modest effects on their avoidance responses to citronellal and citronellol ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Identification of an arthropod molecular target for plant-derived natural repellents

Tian

Wang

Xie

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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Significance Rational control of arthropod pests is important for animal and human health as well as biodiversity preservation. As an alternative to synthetic chemical pesticides, natural repellents represent an ecological method of pest control. Through an exceptional gene library screening in Mesobuthus martensii scorpions, we here uncover a transient receptor potential ion channel as the chemosensory sensor for plant-derived repellents. Its ortholog ion channel in Drosophila melanogaster also acts as a molecular receptor of natural repellents and mediates avoidance behavior. This work thus identifies a molecular basis for arthropod chemosensing and should help update the ecological strategies for pest control while preserving biodiversity.

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“…To the best of our knowledge, this is the first reported example of catnip essential oil repellency studies on blacklegged ticks. The free catnip essential oils repelled 88% of tested ticks 1 h post application, and the repellent effect slightly decreased overtime, still repelling 84% of ticks after 2 h. Catnip oil and main components have been reported to repel blood-feeding pests such as stable flies [ 47 ], mosquitoes [ 31 ], and bed bugs [ 48 ], resulting in a valuable candidate for the development of effective pest-repellent products. This oil has been reported to repel Aedes aegypti L. (Culicidae) ten times more than DEET [ 28 ], and this ability is probably associated with the most effective constituent, nepetalactone.…”

Section: Discussionmentioning

confidence: 99%

“…Catnip oil is one of the few essential oils that have been registered by the EPA as a skin-applied repellent ingredient [ 29 ]. Though there has been extensive research done on the repellency of catnip oil and its main component (e.g., nepetalactone) against mosquitos and other blood-feeding pests, very few studies have focused on the effects of this oil on ticks [ 30 , 31 , 32 ]. Synthetically modified (e.g., hydrogenated) catnip oil components were tested for repellency against mosquitos, stable flies, and ticks ( Ixodes scapularis nymphs), with most of the results focusing on mosquitos [ 33 ].…”

Section: Introductionmentioning

confidence: 99%

Novel β-Cyclodextrin and Catnip Essential Oil Inclusion Complex and Its Tick Repellent Properties

2021

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Cyclodextrin inclusion complexes have been successfully used to encapsulate essential oils, improving their physicochemical properties and pharmacological effects. Besides being well-known for its effects on cats and other felines, catnip (Nepeta cataria) essential oil demonstrates repellency against blood-feeding pests such as mosquitoes. This study evaluates the tick repellency of catnip oil alone and encapsulated in β-cyclodextrin, prepared using the co-precipitation method at a 1:1 molar ratio. The physicochemical properties of this inclusion complex were characterized using GC-FID for encapsulation efficiency and yield and SPME/GC-MS for volatile emission. Qualitative assessment of complex formation was done by UV-Vis, FT-IR, 1H NMR, and SEM analyses. Catnip oil at 5% (v/v) demonstrated significant tick repellency over time, being comparable to DEET as used in commercial products. The prepared [catnip: β-CD] inclusion complex exerted significant tick repellency at lower concentration of the essential oil (equivalent of 1% v/v). The inclusion complex showed that the release of the active ingredient was consistent after 6 h, which could improve the effective repellent duration. These results demonstrated the effective tick repellent activity of catnip essential oil and the successful synthesis of the inclusion complex, suggesting that β-CDs are promising carriers to improve catnip oil properties and to expand its use in repellent formulations for tick management.

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The irritant receptor TRPA1 mediates the mosquito repellent effect of catnip

Abstract: Highlights d Catnip is a broad-acting insect repellent d The repellency is mediated via iridoids such as nepetalactone d Catnip and nepetalactone activate select insect TRPA1 isoforms d TRPA1-deficient mosquitoes show no aversion to catnip

Cited by 37 publications

References 46 publications

Sodium channel activation underlies transfluthrin repellency in Aedes aegypti

Sodium channel activation underlies transfluthrin repellency in Aedes aegypti

Identification of an arthropod molecular target for plant-derived natural repellents

Novel β-Cyclodextrin and Catnip Essential Oil Inclusion Complex and Its Tick Repellent Properties

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