Attenuation of histamine-induced endothelial permeability responses after pacing-induced heart failure: Role for endogenous catecholamines

Objective: After congestive heart failure (CHF), lung endothelial permeabil ity responses to a number of perturbations. including acute, barotrauma, an giotensin II, and thapsigargin are blunted. Our hypothesis was that similar attenuation of permeability responses occurs in peripheral vascular beds a fter CHF. Wr compared peripheral microvascular permeability responses to th e autacoid histamine in control dogs and in dogs paced to heart failure (24 5 bpm for similar to 36 days). Since catecholamines attenuate autacoid-indu ced increases in microvascular permeability in skin and muscle in normal an imals, we also tested whether the known elevation in catecholamines in CHF was involved in any downregulation of permeability responses in this group. Methods: Control and paced dogs were anesthetized, intubated and ventilated , and a hindpaw lymphatic cannulated. The reflection coefficient for total proteins (sigma) was measured at baseline and during one-hour, local intra- arterial histamine infusion. Results: In controls, a fell from 0.83 +/- 0.02 to 0.73 +/- 0.04 after hist amine (p < 0.05), while in the paced group cr was no different from that at baseline (0.77 +/- 0.02). To test whether this difference was due to endog enous catecholamines, dogs were pretreated with propranolol (controls only) or the specific beta(2)-antagonist ICl 118,551 prior to histamine infusion . After beta-blockade, histamine significantly reduced sigma in both contro l (0.83 +/- 0.01 to 0.55 +/- 0.05) and paced (0.83 +/- 0.01 to 0.57 +/- 0.0 7) groups (p < 0.05). Conclusion: We conclude that endogenous catecholamines, acting via beta adr energie receptors, attenuate the permeability response to histamine in paci ng-induced heart failure.