摘要:

A dose-dependent contractile effect of substance P (SP) on the isolated, everted rat portal vein was competitively inhibited by two selective SP antagonists (pro2, phe7, trp9)-SP and (pro4, trp7,9)-SP 4–11. Phentolamine, atropine, methysergide, mepyramine, cimetidine, Sar1, Ile8-angiotensin II, Leu8, des-Arg9-bradykinin and indomethacin did not block the action of SP. However, some of these antagonists differentially reduced SP responses, but such inhibitory effects were shown to be nonspecific. The results suggest that the SP-induced contractions of the rat portal vein were directly mediated by specific receptors localized on the smooth muscle cells. In addition, the response to SP appeared to be independent of prostaglandin biosynthesi

ISSN:0031-7012    

DOI:10.1159/000137885

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Spontaneously hypertensive rats (SHR) were compared to their controls, WistarKyoto (WKY) rats, with respect to contractile responses of aortic preparations and catecholamine concentrations in aorta and superior cervical ganglion (SCG). Contractile responses of aortic preparations to norepinephrine were significantly lower in SHR than in WKY rats, but relaxation responses to isoproterenol were not different. Norepinephrine levels were elevated in SCG and aortas of SHR vs. WKY rats. The results suggest that there are important differences in vascular responses of SHR compared with WKY rats, and raise the question of whether these differences are reflective of transmitter levels and their effects on alpha-adrenergic receptor sensitivity. The results also suggest that lack of beta receptor involvement in the observed alpha receptor desensitization may be important for the development of hypertension in SHR.

ISSN:0031-7012    

DOI:10.1159/000137886

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Grollman hypertension was produced in 15 Sprague-Dawley rats, and chronic 46-week hypertension was observed in these rats. Weekly subcutaneous injections of 1.44 mg indomethacin resulted in significant reduction of the systolic blood pressure 1 h after the injection (p < 0.001). There was no change in the blood pressure following treatment with indomethacin in the 6 normotensive control rats. Light microscopic examinations revealed that adrenal and cardiac tissues were free of serious toxic indomethacin effects. Liver tissue examination showed slight degenerative changes in the indomethacin-treated animals.

ISSN:0031-7012    

DOI:10.1159/000137887

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

In gerbils, ‘minor’ (myoclonic) and ‘major’ (clonictonic) seizures were induced by blowing at the animals with compressed air. The anticonvulsant ED50 of the following drugs was determined after oral administration against both types of seizures: phenytoin, phenobarbital, carbamazepine, sodium valproate, ethosuximide, and diazepam. Valproate, ethosuximide, and diazepam were most potent against ‘minor’ seizures which could not or only partially be suppressed by phenytoin or carbamazepine, respectively. The ‘grand maΓ drugs phenytoin, phenobarbital, and carbamazepine were, on the other hand, more potent against ‘major’ than against ‘minor’ seizures. When phenobarbital was administered for several days, a strong induction of hepatic micro

ISSN:0031-7012    

DOI:10.1159/000137888

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Infusion of diazoxide, a potent benzothiazide antihypertensive, into the renal artery results in diuresis and natriuresis. The site within the nephron of decreased reabsorption has been controversial. Thus free flow recollection micropuncture studies of the superficial proximal tubule of the dog were undertaken to determine if diazoxide decreased sodium reabsorption from this part of the nephron. Renal blood flow, monitored by an electromagnetic flow meter, was increased by about 15 % with the diazoxide infusion. Systemic blood pressure and hematocrit remained unchanged. Glomerular filtration rate increased significantly from 26 ± 2 to 34 ± 3 ml/min, urine flow and sodium excretion also increased (0.13 ± 0.01 to 0.33 ± 0.06 ml/min and 5.5 ± 0.90 to 35.5 ± 11.0 μEq/min, respectively). Decreased sodium reabsorption from the proximal tubule was demonstrated by a decrease in the tubular fluid to plasma inulin ratio (1.62 ± 0.1 to 1.47 ± 0.1) thus giving a reduction in fractional sodium reabsorption to the site of micropuncture (36.1 ± 4.3 to 29.5 ± 5.1 %, p < 0.05). To examine peritubular effects of diazoxide infusion, capillary protein concentration and pressure were measured; the former increasing significantly (9.17 ± 0.32 to 9.80 ± 0.35, p < 0.05) and the latter did not change (13.1 ± 1.0 vs. 15.1 ± 1.4 mm Hg). Thus intrarenal diazoxide causes whole kidney vasodilatation with diuresis, natriuresis and decreased sodium reabsorption from the superficial proximal tubule. Additional studies provided no data to indicate that changes in peritubular physical factors account for the changes in sodium handling. Because diazoxide is structurally related to the thiazide diuretics and since such diuretics can alter proximal tubular sodium reabsorption, the data are consistent with a direct effect of diazoxide on the superficial p

ISSN:0031-7012    

DOI:10.1159/000137889

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The effects of verapamil on calcium transport and uptake in duodenal and jejunal segments of intestine in young male rats were determined using the everted gut-sac technique. Verapamil added to both the mucosal and serosal surface of duodenal segments decreased calcium transport and tissue uptake in a dose-related fashion over a concentration range of 1–2 mM. In jejunal segments verapamil (1 mM) added to both the mucosal and serosal surface reduced calcium transport but did not alter tissue uptake. Similarly, verapamil (1 mM) added to either the mucosal or serosal surface alone in duodenal segments reduced transport but did not depress tissue uptake. The results of this study indicate that verapamil alters calcium translocation in intestinal tissue in a fashion which is similar to that reported in other biological tissu

ISSN:0031-7012    

DOI:10.1159/000137890

出版商:S. Karger AG    

年代:1983

数据来源: Karger

ISSN:0031-7012    

DOI:10.1159/000137891

出版商:S. Karger AG    

年代:1983

数据来源: Karger

ISSN:0031-7012    

DOI:10.1159/000137892

出版商:S. Karger AG    

年代:1983

数据来源: Karger

ISSN:0031-7012    

DOI:10.1159/000137884

出版商:S. Karger AG    

年代:1983

数据来源: Karger