Hemodvnamic and Resperatory Responses of Dogs to Hemorrhage After Treatment With Dihydroergotoxine and Naloxone
The endogenous opiate receptor antagonist (naloxone, NAL) and alpha-adrenergic receptor antagonist (dihydroergotoxine, DHETX) were infused separately or simultaneously in dogs to determine their effects in hemonhagic shock. Mean arterial pressure, heart rate, electrocardiogram, respiratory rate, haematocrit and plasma protein concentration were measured during sustained posthemorrhagic hypotension (180 min, 40 mmHg) in 22 dogs. Animals were divided into four groups: DHETX-treated (n=6), NAL-treated (n=5), DHETX+NAL-treated (n=5), and SAL (saline)-treated (control group, n=6). The treatment was performed before bleeding. After 3 hours of posthemorrhagic hypotension, ali shed blood was returned to the dogs, and animals passed through a postretrasfusion period for 60 min. The animals which survived experimental procedure were observed in next 24 hours. Under the present experimental conditions, prophylactic administration of DHETX had better effects on preservation of parameters measured and survival of dogs than NAL, while DHETX+NAL treatment had the worst effects (no one dog survived).