Figure 4.

Autocrine ACh acts via nAChRs to elicit [Ca²⁺]_i transients in MOLT-3 cells. (A) Spontaneous increases in [Ca²⁺]_i within MOLT-3 cells during a 5-min observation period. Representative traces showing the spontaneous [Ca²⁺]_i responses. Reproduced with permission from [61]. (B) ACh synthesized by ChAT and then released from T cells activates nAChRs on the surfaces of themselves or neighboring cells, which results in transient [Ca²⁺]_i increases and IL-2 synthesis. TCR activation enhances the autocrine action of ACh by mediating increased ChAT expression.