Glycaemic index of conventional carbohydrate meals.

The glycaemic index (GI) and the triacylglycerol response were measured in thirty non-insulin-dependent diabetes mellitus patients given 50 g portions of five different conventional Indian meals containing semolina (Triticum aestivum) cooked by two different methods, or combinations of semolina and pulse (black gram dhal (Phaseolus mungo), green gram dhal (Phaseolus aureus) or Bengal gram dhal (Cicer arietum)). There were no significant differences among meals in mean GI except for meals based on roasted semolina or semolina-black gram dhal. Compared with the blood glucose response for a 50 g glucose load, only meals based on steam-cooked semolina and semolina-Bengal gram dhal elicited a significantly lower response at 1 h postprandially, and only meals based on semolina-black gram dhal at 2 h postprandially. No significant differences were found among the meals in the triacylglycerol-response.

Glycemic index of traditional Indian carbohydrate foods.

The glycemic index (GI) was determined in 36 non-insulin-dependent diabetes mellitus patients who were fed 50 g carbohydrate portions of six Indian conventional foods, including rice, a combination of rice-legume (Bengalgram, peas, and greengram), and a combination of rice-dal (greengram dal and redgram dal -- dal is dehusked and split legume). In addition to the GI, triglyceride (TG) responses of these foods were also determined. A higher GI was obtained for rice and for rice with peas; all other combinations yielded lower glycemic indices. However, all the foods produced significantly lower blood glucose response 2 hours postprandially as compared with blood glucose responses to a 50 g glucose load for the same group. No significant difference was observed for TG responses to the different foods.

Self-stimulation responses are altered following long-term but not short-term treatment with clorgyline.

Clorgyline (a selective monoamine oxidase-inhibiting antidepressant) given chronically facilitated hypothalamic self-stimulation in rats, while acute treatment was without effect. Furthermore, long-term but not short-term clorgyline treatment significantly attenuated the suppressive effect of the selective alpha 2-adrenergic agonist clonidine on this behavior. These findings suggest that adaptative alterations in the modulation of rewarded behavior by inhibitory presynaptic noradrenergic receptors may be involved in antidepressant efficacy.

Actions and interactions of cocaine on self-stimulation behavior in rats.

The effect of cocaine, over a dose range of 2--60 mg/kg, i.p., on self-stimulation (SS) behavior was studied in rats with electrodes either in the posterior hypothalamus (PH, monoaminergic) or the area ventralis tegmentum (A10, dopaminergic). The drug increased SS behavior with peak effects at 30 mg/kg in PH rats and 20 mg/kg in A10 rats. Azaperone (an alpha-adrenergic blocker) and haloperidol (an antidopaminergic neuroleptic) given at doses that did not affect baseline SS responses reduced cocaine-induced enhancement of SS in both PH and A10 rats, showing the involvement of both noradrenergic and dopaminergic mechanisms in SS behavior. A scopolamine dose that itself facilitated SS responding enhanced the effect of cocaine on this behavior, thus suggesting an additional involvement of cholinergic mechanisms in cocaine effect.

Carcinogenicity of some folk medicinal herbs in rats.

Twelve medicinal herbs were bioassayed to correlate a high incidence of esophageal carcinoma in natives of different places with their habitual consumption of these products. Outbred NIH Black rats were given 72 weekly sc injections of the total aqueous extracts of the plant materials. The tanninrich plant extracts from Areca catechu and Rhus copallina produced local tumors in 100 and 33%, respectively, of the experimental animals. Other materials included Diospyros virginiana and extracts from plants not rich in tannins. Diospyros and extracts of Sassafras albidum and Chenopodium ambrosiodes were tumorigenic in over 50% of the treated animals.

Carcinogenicity of Camellia sinensis (tea) and some tannin-containing folk medicinal herbs administered subcutaneously in rats.

In an attempt to correlate the high incidence of esophageal carcinoma in natives of certain places with their habit of using herbaceous folk medicines, we performed bioassays of several plant extracts and the fractions prepared from them. Fourteen extracts and fractions from 6 plants were injected sc into NIH Black rats. The tannin fractions from Quercus falcata pagodaefolia, Diospyros virginiana, and Camellia sinensis were very active and produced tumors at the injection site in 66% or more of the treated animals. Tannin fractions from 3 other plants and total aqueous extracts from 5 to 6 tested plants were also tumorigenic rats. The induced tumors were malignant fibrous histiocytomas similar, if not identical, to those encountered in humans. The experiment indicated a possibility of induction of tumor in man by the tested plant materials.

Temporal and regional differences in brain concentrations of lithium in rats.

Lithium (Li) concentrations have been estimated in several peripheral tissues (serum, heart, kidney, liver and skeletal muscle) and different brain areas (cortex, caudate nucleus, hypothalamus, diencephalon, midbrain, pons-medulla and cerebellum) at different intervals (0.5 to 48 h) after administrations of 3 mEq/kg of lithium chloride (LiCl). The Li concentrations in the brain areas increased gradually, reaching their peak at 8 h; the hypothalamus showed the highest concentration measured between 0.5 and 8 h; after 8 h the highest concentration was observed in the caudate nucleus, followed approximately by those of the cortex, rest of the diencephalon, and other areas. Concentration of Li in the skeletal muscle, although initially less, was maintained at a higher percentage of the initial level for more than 24 h compared to the other peripheral tissues.

Interactions of adrenergic stimulants and blockers on self-stimulation behavior in rats.

Self-stimulation behavior in rats was facilitated by two adrenergic stimulants, amphetamine (0.5 or 1 mg/kg, intraperitoneal, i.p., or 100 mug, intracerebroventricular, i.c.v.) and cocaine (5 mg/kg, i.p.). Three alpha-adrenergic blockers (phenoxybenzamine, dibenamine, phentolamine) and a beta-adrenergic blocker (propranolol) decreased self-stimulation responding at 100 mug i.c.v. doses, but showed very little effect at small i.p. doses. Pretreatment with alpha- and beta-adrenergic blockers (i.c.v.) also decreased amphetamine-facilitated responding. The effects of amphetamine or cocaine (i.p.) were not significantly altered by these blockers at the doses used. The depressant effects of the alpha- and beta-adrenergic blockers on self-stimulation behavior appear to be nonspecific with respect to the type of adrenergic receptors.

Effects of microinjection of ouabain into the hypothalamus in cats.

1. In cats anaesthetized with chloralose, repeated injections of 20 mug ouabain were made either into the cerebral ventricles, or into the ventromedial nucleus of the hypothalamus (VMH), or intravenously whilst the electrocardiogram, arterial blood pressure and respiration were recorded.2. The injections produced cardiac arrhythmias preceded by sinus bradycardia, variable changes in arterial blood pressure and respiratory depression. Death occurred either from ventricular fibrillation or from cardiac arrest.3. The arrhythmias which occurred after the injections into the cerebral ventricles were not peripheral effects produced after absorption of the ouabain into the blood stream, because with intravenous injections larger amounts were required to produce the arrhythmias and to cause death than with intraventricular injections. The arrhythmias which resulted in death were due to an action on the VMH. With microinjections of ouabain into this region of the brain death occurred earlier and after smaller doses than after intraventricular injections.4. While sinus bradycardia was abolished by bilateral vagotomy other cardiac arrhythmias were prevented by acute cardiac sympathectomy and cervical cord transection. Thus both the sympathetic and parasympathetic nervous systems appear to be involved in the production of these arrhythmias.5. Since some of the cardiac arrhythmias obtained with ouabain in anaesthetized cats resemble the cardiotoxic effects seen in clinical practice during treatment with digitalis glycosides it is concluded that these effects, too, are, at least in part, central in origin, caused by an action on the VMH and mediated mainly via the sympathetic nervous system.