Galanin in the regulation of pancreatic vascular perfusion

Objectives: Acute pancreatitis is associated with compromised pancreatic microcirculation. Galanin is a vasoactive neuropeptide, but its role in the regulation of pancreatic vascular perfusion (PVP) is unclear. Methods: Localization of galanin immunoreactivity was investigated by immunohistochemistry, and the effects of bolus doses of galanin or the antagonist galantide on blood pressure (BP) and PVP (by laser Doppler fluxmetry) were determined in anesthetized possums. Results: Galanin immunoreactivity was abundant in the possum pancreas particularly around blood vessels. Galanin (0.001-10 nmol) produced a dose-dependent increase in BP (to 177% of baseline) and a complex PVP response consisting of a transient increase, then a fall below baseline with recovery to above baseline. Galantide (0.003-30 nmol) caused a dose-dependent biphasic response in BP, with a reduction, recovery, then a further fall, followed by recovery, whereas PVP increased (178%) then fell (to 56%) of baseline. Similar effects were produced by continuous intravenous infusion of galanin (1 and 10 nmol) or galantide (3 and 30 nmol). The second-phase response of these agents is probably a passive response of the pancreatic vasculature to systemic cardiovascular effects. Conclusions: These data suggest that galanin acutely reduces PVP, whereas galantide increases it, implying galanin may be important in the regulation of PVP.