Spatial distribution of the cannabinoid type 1 and capsaicin receptors may contribute to the complexity of their crosstalk
Chen J, Varga A, Selvarajah S, Jenes A, Dienes B, Sousa-Valente J, Kulik A, Veress G, Brain SD, Baker D, Urban L, Mackie K, Nagy I.
The cannabinoid type 1 (CB1) receptor and the capsaicin receptor (TRPV1) exhibit co-expression and complex functional interactions in a sub-population of primary sensory neurons (PSN). CB1 and TRPV1 form two distinct subpopulations based on their properties that could be due to the distribution pattern of the two receptors. Pharmacologically, neurons respond either only to capsaicin or to both capsaicin and anandamide (ACRN). Blocking or deleting the CB1 receptor only reduces both anandamide- and capsaicin-evoked responses in ACRNs. Deleting the CB1 receptor also reduces the proportion of ACRNs without any effect on the overall number of capsaicin-responding cells. Regarding the distribution pattern of the two receptors, neurons express CB1 and TRPV1 receptors either isolated in low densities or in close proximity with medium/high densities. We suggest that spatial distribution of the CB1 receptor and TRPV1 contributes to the complexity of their functional interaction.
