“…The VIPR1 and VIPR2 genes encode receptors that respond equally to VIP and PACAP named VPAC1 and VPAC2 respectively (Ishihara et al, 1992; Lutz et al, 1993; Sreedharan et al, 1993; Couvineau et al, 1994), whereas the ADCYAP1R gene encodes the PACAP-preferring receptor PAC1 (Hashimoto et al, 1993; Hosoya et al, 1993; Pisegna and Wank, 1993). In mammals, both peptides are widely expressed in the central and peripheral nervous systems (Pozo and Delgado, 2004; Laburthe et al, 2007; Dickson and Finlayson, 2009; Vaudry et al, 2009), are also produced within immune cells where they play the role of a ‘cytokine-like peptide’ (Gomariz et al, 2001; Delgado et al, 2004b), and are induced in both neurons and immune cells during inflammation (Gomariz et al, 1993; Gaytan et al, 1994; Leceta et al, 1996; Zhang et al, 1998; Vassiliou et al, 2001; Abad et al, 2002; Armstrong et al, 2004; Delgado et al, 2004b; Laburthe et al, 2007; Vaudry et al, 2009). Likewise, their receptors are mainly distributed in the nervous, endocrine and immune systems (Delgado et al, 2004b; Laburthe et al, 2007; Vaudry et al, 2009).…”