Ca2+ uptake and distribution in alloxan-diabetic rat arterial and venous smooth muscle

Summary This report demonstrates that in experimental diabetes mellitus (DM) calcium uptake and its distribution is altered in rat aortic but not in portal venous smooth muscle. Results are interpreted as consequences of increased calcium binding by aortic smooth muscle in experimental DM, which could account for the hyporeactivity of alloxan diabetic rat aorta reported previously.Supported by NIH grant No.HL-18015 and NIDA grant No. DA-02339.     

Ethanol reduces Ca2+ concentrations in arterial and venous smooth muscle

Summary The present results, using isolated rat aortic strips and portal vein segments, demonstrate that ethanol (170–430 mM) significantly inhibits calcium uptake in these 2 different types of vascular smooth muscle.Supported by NIH grant No. HL-18015 and NIMH grant No. MH-26236. Request for reprints should be addressed to B.M. Altura.     

Effect of pectin and cellulose on formation and regression of gallstones in hamsters

Summary Male Syrian hamsters were fed a lithogenic diet containing 7% cellulose or 4.2% pectin. After 50 days, pectin was 76% and cellulose 64% less lithogenic than the control diet. Hamsters fed the control diet for 50 days were maintained on that diet for another 50 days or fed diets containing cellulose or pectin. These was a 52% increase in gallstone incidence in hamsters continued on the control diet and a 9% increase in those on cellulose. Pectin promoted regression of gallstones (by 52%).Acknowledgments. This work was supported, in part, by a grant (HL-03299) and a Research Career Award (HL-00734) from the National Institutes of Health, and by funds from Mary L. Smith and the Commonwealth of Pennsylvania.     

Inhibition of neurotensin (NT)-induced glucagon release by [D-Trp11]-NT1

Summary A synthetic analog of neurotensin (NT), [D-Trp¹¹]-NT, antagonized NT-induced hyperglucagonemia and hyperglycemia, and also NT-induced glucagon release from pancreatic islets in rats.This work was supported in part by a grant from the Imanaga Medical Research Foundation, Nagoya, Japan. Address for reprint requests: M.U., Department of Surgery, National Nagoya Railway Hospital, Taiko 1-chome, Nakamura-ku, Nagoya 453, Japan.     

Increased blood pressure in the SHR is not related to a deficit in renomedullary PGE2

Summary Synthesis of prostaglandin E₂ by renal medulla from SHR and WKY rats was compared during early postnatal development. Although arterial blood pressure was significantly higher in SHR as early as 6 weeks of age, no difference in renal medullary prostaglandin synthesis was observed.Supported in part by a grant from the michigan Heart Association and NIH grant AM-10913.     

Effect of angiotensin II on neonatal lamb carotid arteries

Summary Isometric tension was measured in arterial strips from neonatal lambs and adult sheep, after stimulation by angiotensin II. During the early maturation period immediately following birth (3 weeks) there was a progressive increase in sensitivity to the agent.This study was supported by the Golden Empire Chapter of the American Heart Association and the United States Public Health Service, grant No. PHS HL 14780-03.     

Baroreceptor reflex sensitivity after acute blood volume expansion in anesthetized dogs

Summary Changes in heart rate resulting from mechanically induced changes in arterial blood pressure were used as a measure of baroreflex sensitivity. This sensitivity was shown to be decreased after volume expansion.This work was supported in part by PHS grant HL-23239 and a grant from the Central Ohio Heart Chapter of the American Heart Association.     

Angiotensin II in the hippocampus. A histochemical and electrophysiological study

Summary The presence of the renin angiotensin system in the hippocampus is shown by immunohistochemistry. Intra- and extra-cellular recordings revealed that angiotensin II and III excite CA 1 pyramidal cells by disinhibition. The effect is antagonized by [Sar¹, Thr⁸]-A II.This work was supported by grant Nos 3.271.78 and 3.396.78 of the Swiss National Science Foundation and research grant HL-24112 from NIH. T. Inagami was a visiting scientist of the Roche Medical Research Foundation.     

Ethanol-induced changes in plasma glucose,insulin and glucagon in fed and fasted rats

Summary Orally administered ethanol produced dose-related suppression of IRI levels and elevation of IRG levels in fed and fasting rats. Plasma glucose levels were unaffected in the fasting rats, but a moderate hyperglycemic response accompanied the decline in IRI and the rise in IRG observed in the fed rats.This research was supported in part by a grant from the National Institute on Alcohol Abuse and Alcoholism (AA-3218) and by a supplemental grant from the National Council on Alcoholism.     

Sodium-dependence of sustained force in potassium contracture of cat ventricle

Summary Following exposure to low-Na solution, the initial phase of K-contracture in cat ventricle is prominent while the second (sustained) phase is markedly attenuated. Monensin, a Na-specific ionophore, enhances the second phase of K-contracture following exposure to low-Na solution.This study is supported by NIH grant HL-19044 and a Grantin-Aid from the American Heart Association-Greater Miami Affiliate.The authors wish to thank Ms Diane Rodman for invaluable technical assistance.     

Effect of exercise training on the chronotropic response of isolated rat atria to atropine

Summary Atria isolated from rats after 7 weeks of exercise training beat at a slower rate than did atria from sedentary controls. Atria from exercised rats showed a significant acceleration in response to atropie.This study was supported by a grant from the Genesee Valley Heart Association.     

The effects of phenoxybenzamine on the aortic pressure-diameter relationship in dogs

Summary The normalized diameter (D/D_13.3 where D_13.3 equals D at 13.3 kPa under control conditions) was measured at selected pressure levels under different hemodynamic conditions. Hemorrhage caused the normalized diameter to decrease (–3.3%) when compared to control values at a given pressure. Volume expansion anda-blockade with phenoxybenzamine caused D/D_13.3 to increase (+3.3% and +8.5% respectively).This work was supported in part by PHS grant HL-23239 and a grant from the Central Ohio Heart Chapter of the American Heart Association. To whom reprint request should be addressed.     

Effect of organophosphate pesticide Sumithion (Fenitrothion) on some aspects of carbohydrate metabolism in a freshwater fish,Sarotherodon (Tilapia)mossambicus (Peters)

Summary A lethal (Lc₅₀/48 h — 6 mg/l) concentration of the organophosphate (OP) pesticide Sumithion increased blood glucose levels and phosphorylase activity, but hepatic glycogen registered a fall which indicated that the observed hyperglycemia was due to breakdown of hepatic glycogen.This work was supported by UGC grant to R.R.     

Hepatic blood flow in acute myocardial ischemia

Summary Hepatic blood flow was monitored in cats during myocardial ischemia (MI). Increased plasma CPK activity, the S-T segment of the electrocardiogram, and hepatic flow was reduced by 5 h to 40% of control. The results suggest that MI can influence organs distant from the original ischemic episode.Supported in part by Research grant HL-17745 from the National Heart, Lung and Blood Institute of the National Institutes of Health.Acknowledgments. We gratefully acknowledge the expert technical assistance of Mary Ann Spath.     

Differentiation in renal homografts of isolated parts of rat embryonic ectoderm

Summary The central and the peripheral areas of the head-fold stage rat embryo ectoderm develop into both the neural tissue and the epidermis when grafted under the kidney capsule of adult rats.This investigation was supported by the grant No. IV/3 from the Research Foundation of S.R. Croatia, and in part by NIH PL 480 Agreement No. 02-038-1.     

Vascular reactivity in hypertension: Altered effect of ouabain

Summary Ouabain inhibits the relaxing effect of Ca²⁺ (but not of Mn²⁺) on contractile responses in tail artery strips isolated from spontaneously hypertensive and normotensive rats. The magnitude of ouabain inhibition was greater in vascular strips from hypertensive rats suggesting a significant difference in basic membrane function in hypertensive vascular smooth muscle.These studies were supported by National Heart, Lung, and Blood Institute grants HL-03765 and HL-18575-02-03. R.C. Webb is a Postdoctoral Research Fellow of the Michigan Heart Association.     

Effects of sera and liver extracts from partially hepatectomized rats on liver slice DNA synthesis

Summary Sera from partially hepatectomized rats (PH) compared to sera from control rats (C) enhance liver slice DNA synthesis but depress kidney slice DNA synthesis. Alone, liver extracts from PH do not affect DNA synthesis; but adding sera to PH extracts stimulates, suggesting that sera and liver factors from PH may participate in compensatory growth.Acknowlegments. Supported by NIH, grant AM 15458, a grant from the Washington Heart Association, and Public Health Service, grant RR 5360 (Medical). The authors wish to express their appreciation to Angelina Vasques for technical assistance and Betty Mendelson, Patti Werr and Susan Dreux for secretarial help.     

Control of the hypothalamus-pituitary-adrenal axis in young and older rats injected with thyroxine1–3

Summary Administration of T₄ on alternate weeks for 30 weeks at a dosage which does not alter body weight depresses basal serum corticosterone levels in older rats (575 days), but not in young animals (260 days). Similar serum corticosterone response to HPA axis stimulation occurs regardless of age or T₄ injection.Presented in part at the 8th Annual National Meeting of the American Aging Association, October 1978, San Francisco.Supported by an FRC grant, Graduate College, Bowling Green State University.Acknowledgment is made of the technical assistance of L. Carter, P. Froelich, R. Froelich, J. Ku, M. Meserve and D. Schulte.     

Plasma lecithin: cholesterol acyltransferase activity in high-and low-responding rhesus monkeys

Summary The initial rate of esterification of plasma cholesterol by lecithin: cholesterol acyltransferase (LCAT) was measured in high- and low-responding rhesus monkeys fed a moderately high cholesterol (0.15 mg/kcal) diet. The results show that the rate of esterification of cholesterol in the plasma of the high-responders was significantly (p<0.025) higher than that of the low-responding animals. In view of known relationships between LCAT activity and plasma lipoprotein metabolism, it is suggested that the lipoprotein metabolism in the high-responders would differ from that in the low-responders.Acknowledgments. Financed by USPHS research grant HL-08974 from the National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md.     

Comparison of diurnal and nocturnal rates of 5-hydroxytryptamine turnover in the rat mediobasal hypothalamus

Summary Rates of 5-hydroxytryptamine (5-HT) turnover in the mediobasal hypothalamus of male rats were estimated using pharmacological methods during the daytime and at night. Concentrations of 5-HT in this hypothalamic area were higher nocturnally than diurnally; this was apparently due to increased 5-HT synthesis and decreased 5-HT catabolism at night.Supported by NIH grant RR07187 (TSK) and NIH grant HD10202 (Neuroendocrine Core).