Mosquito bites usually cause little pain and only feel itchy after being bitten.Although the mosquito's stinger is long, it is said that it is hard to feel pain because it is thin (painless puncture).The saliva released when a mosquito stings makes it difficult for blood to clot and has the effect of releasing histamine, which causes itching.However, the involvement of mosquito saliva components in painless puncture was unknown.

　The capsaicin receptor TRPV1 and wasabi receptor TRPA1 in the sensory nerves are pain receptors and may be involved in analgesia.Therefore, the research group used mosquitoes and mice to investigate the effects of saliva on TRPV1 and TRPA1.As a result, it was found that mosquito saliva suppresses the functions of human TRPV1 and TRPA1 in a concentration-dependent manner, and mouse saliva also suppresses the functions of mouse TRPV1 and TRPA1.Furthermore, it was found that the analgesic protein called sialolphin contained in saliva is a promising candidate for a component that inhibits the functions of TRPV1 and TRPA1.

　In addition, pain-related behavior caused by administration of capsaicin and wasabi components to the soles of the feet of mice and spinal nerve excitement caused by mechanical stimulation of the feet of rats were also suppressed by mosquito saliva.In addition, sialolfin suppressed the nerve excitement of the rat spinal cord by capsaicin.

　From this, it was concluded that saliva from mosquitoes and mice inhibits the functions of the pain sensors TRPV1 and TRPA1 to provide analgesia.Many animals, such as humans, lick their wounds when injured, which may be saliva-induced analgesia.It is expected that research on saliva-containing components such as sialolphin will lead to the development of new analgesics.

Paper information:[PAIN] Inhibition of TRPV1 and TRPA1 by mosquito and mouse saliva