Figure 4.
illustrates the possible mechanisms that underlie VIP’s actions in SCN neurons. In all cases, we expect that VIP would activate VPAC2R to stimulate the AC/PKA signaling pathway. This VIP-activated cascade has at least three actions within the SCN including modulation of intrinsic voltage gated channels, presynaptic regulation of GABA release, and alterations in transcription via CREB.