Heat/pain receptor
Capsaicin-sensitive nociceptor channel
Also searched as Capsaicin-sensitive nociceptor channel.
The route, and it is proven at every link. Eating capsaicin does not deliver it to fat. It opens TRPV1 on sensory nerves in the gut wall. Those vagal fibers carry the signal to the nucleus tractus solitarius in the brainstem, which sets sympathetic tone to brown fat, which releases noradrenaline, which raises cAMP and drives UCP1. Every step has been broken on purpose to test it: the response disappears with beta-blockers, with cutting the vagal afferents, and in animals lacking either TRPV1 or UCP1 itself. Three channels, three flavors. TRPV1 answers to chilli. TRPA1 answers to cinnamon. TRPM8 answers to menthol. A randomized double-blind crossover trial gave all three to healthy people and measured energy expenditure by indirect calorimetry alongside autonomic activity — the pungent and the cooling both reach the same nerve. What must be said against it. The sign can reverse. In one line of work TRPV1 activation at the vagal ending excites brainstem neurons that inhibit sympathetic outflow to brown fat rather than raising it, and the same is reported for GLP-1 acting on the same nerves. The supplement literature is openly described as conflicting, with some trials finding the converse of what is expected. Most of the animal work was done at 21 degrees, which is cool for a mouse but thermally neutral for a clothed adult, so it may not carry across. And the fat-reducing effect differs by TRPV1 genotype — it is not the same door for everyone.
In depth
TRP sensory channels in the gut wall — the entry point where pungent and cooling plant compounds start a nerve signal that ends in heat.
What drives it
Gut barrier increases it.
oral administration of capsaicin and/or capsinoids can activate TRPV1 expressed in sensory nerves within the gastrointestinal tract and increase sympathetic nerve activity innervating BAT. 10.3389/fendo.2020.00222. doi 10.3389/fendo.2020.00222
What it drives
It increases Gut-brain signal.
Gastrointestinal vagal afferents have central endings in the nucleus tractus solitarius (NTS). The NTS has projections to BAT where it regulates the sympathetic tone to BAT and has been directly implicated…. 10.3389/fendo.2020.00222. doi 10.3389/fendo.2020.00222
It increases Sympathetic drive.
These responses are blunted by the administration of beta-adrenergic blockers or through the denervation of vagal afferents and extrinsic nerves connected to the jejunum. It was also reported that the…. 10.3389/fendo.2020.00222. doi 10.3389/fendo.2020.00222
Blends that modulate it
Each blend page names this pathway and carries the study behind its claim.
See it on the map
Open the causal map to follow this pathway upstream and downstream, arrow by arrow, each with its study.