PACAP 1-38 acetate is a pituitary adenylate cyclase activating polypeptide (PACAP) analogue. PACAP 1-38 acetate binds to PACAP type I receptor(IC50 = 4 nM) and PACAP type II VIP2 receptor(IC50 = 1 nM) but not to PACAP type II, VIP1 receptor.

PACAP type II VIP2:1 nM, PACAP type I:4 nM

The ability of neuropeptides to modulate enteric smooth muscle proliferation was examined in primary explant cultures of rabbit gastric antrum and colon smooth muscle. Cell proliferation was determined by [3H]thymidine incorporation measurements and cell counting. PACAP 1-38 acetate concentration dependently (10(-10)M to 10(-6)M) inhibited the serum-induced [3H]thymidine incorporation [in colon, 55.6 +/- 9.3% of control with 10(-7)M PACAP 1-38 acetate] and inhibited increase in cell numbers in cultures derived from the colon but not in those from the antrum. Effects of PACAP 1-38 acetate were mimicked by forskolin (10(-7) to 10(-6) M) but not by 8-bromo-cGMP. Substance P, motilin, calcitonin gene-related peptide, and somatostatin had no effect[3].

The effect on total pulmonary resistance (R1) was examined for inhaled PACAP 1-38 acetate in anesthetized, ventilated guinea pigs. Two minutes after inhalation, PACAP 1-38 acetate (36 +/- 6%) inhibited the increase in R1 (% inhibition of histamine-induced R1 prior to inhalation) caused by histamine i.v., whereas the vehicle (-1 +/- 10%) did not. The inhaled peptides caused no sustained effects on heart rate or blood pressure. Infusion of PACAP 1-38 acetate i.v. dose-dependently inhibited the increase in R1 caused by inhaled histamine and by carbachol i.v.[4].

H2O: 100 mg/mL, Sonication is recommended.