摘要:

The effects of two selective thromboxane (Tx) A2 antagonists (SQ 29,548 and SQ 28,668) on endotoxin-induced pulmonary hypertension were determined in anesthetized pigs. SQ 29,548 (10 µg/kg/min, i.v., n = 6) or vehicle (n = 7) was infused from 15 min before until 60 min after an intravenous infusion of Salmonella enteritidis endotoxin (1.0 µg/kg). Within 20 min, vehicle-treated animals developed an acute 350 ± 25% increase in pulmonary vascular resistance (PVR) with a 43% survival rate. In the presence of SQ 29,548 this initial pulmonary vasoconstriction was absent and all animals survived. However, a delayed increase in PVR of 58 ± 20% was detected. The primary manifestation of the increase in PVR was an increase in pulmonary arterial pressure. In a similar preparation, septicemia was produced by Escherichia coli endotoxin (0.5 µg/kg, i.v.) and SQ 28,668 (3, 10, 30 or 100 µg/ kg/min, i.v., n = 5–6 per dose level) and vehicle (n = 6) treatments were compared. SQ 28,668 doses of 30 and 100 µg/kg/min mitigated the early, but not late, increases in PVR. These data demonstrate that endotoxemia in pigs produces an initial TxA2-receptor-dependent vasoconstriction and also a more slowly developing pulmonary hypertension which is probably due to other m

ISSN:0031-7012    

DOI:10.1159/000138284

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

At 4 h following induction of pleural inflammation in rats using either an immune stimulus (reverse passive Arthus reaction, RPAR) or a chemical stimulus (carrageenan), the cellular infiltration and fluid accumulation responses were quantitated. The bell-shaped antigen (BSA) dose-response curve describing the fluid response was increased upward as the anti-BSA dose was increased from 0.25 to 1 mg, whereas the dose-response curve for cellular infiltration was both shifted upward and to the right. Both nonsteroidal anti-inflammatory drugs and a mixed lipoxygenase-cyclooxygenase inhibitor (BW 755C) preferentially inhibited fluid accumulation in RPAR pleurisy elicited with 5 mg BSA and 1 mg anti-BSA and in carrageenan pleurisy. In contrast, these drugs inhibited cellular infiltration preferentially in RPAR pleurisy elicited with 1 mg BSA and 1 mg anti-BSA. These results demonstrate that the fluid and cellular responses in rat pleural inflammation can be differentially regulated by anti-inflammatory drugs depending upon the doses of antigen and antibody employed in RPAR pleurisy and the identity of the inflammatory stimulus.

ISSN:0031-7012    

DOI:10.1159/000138285

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Combined administration of verapamil, a phenylalkylamine calcium-entry antagonist, with a pure beta-adrenoceptor blocker, propranolol, produces profound cardiovascular depression associated with decreased hepatic clearance of both drugs. We have therefore studied the combination of verapamil and pindolol, a beta-adrenoceptor blocker with intrinsic sympathomimetic activity (ISA), to evaluate whether or not the property of ISA will confer protection from the usual toxic effects observed with verapamil and a beta-adrenoceptor blocking agent. In an anesthetized dog model, dosing regimens which produced stable plasma concentrations of either verapamil and/or pindolol resulted in drug effects which were closely related to the plasma levels of the individual agents. When pindolol was combined with verapamil, profound depression of cardiac pump function occurred, similar to that previously found with propranolol. Further, plasma concentrations of verapamil promptly increased into a toxic range during combined administration with pindolol. In summary, since the cardiovascular depression resulting from verapamil and pindolol in combination is similar to that which occurs with verapamil and propranolol, ISA does not appear to obviate the toxic effects of verapamil and a beta-adrenoceptor agent in combination.

ISSN:0031-7012    

DOI:10.1159/000138286

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Our previous experiments demonstrated that chronic ethanol treatment of rats produces tolerance to the in vitro inhibitory effects of ethanol on norepinephrine-, KCl–, and electrically evoked contractions of the vas deferens. In the present study, ethanol dependence also resulted in subsensitivity of the vas to the effects induced by α2-adrenoceptor agonist clonidine, the α-receptor antagonists phentolamine and phenoxybenzamine, as well as to adenosine and naloxone. These results indicate that the biochemical mechanisms of ethanol express themselves at both the pre- and postjunctional level involved in the modulation of neurotransmission in the rat vas defer

ISSN:0031-7012    

DOI:10.1159/000138287

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:0031-7012    

DOI:10.1159/000138288

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:0031-7012    

DOI:10.1159/000138289

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:0031-7012    

DOI:10.1159/000138283

出版商:S. Karger AG    

年代:1987

数据来源: Karger