Some pharmacological studies on the effects of Cerastes vipera (Sahara sand viper) snake venom.

The effects of the venom of the Sahara sand viper (Cerastes vipera) were studied on isolated chick biventer cervicis, isolated rat atria and vas deferens preparations, and on the electrocardiogram of anaesthetized rats. Effects on 3H-noradrenaline uptake were studied using rat brain synaptosomes. At 50 micrograms/ml and 100 micrograms/ml, the venom caused a transient increase in rate and force of contractions of the rat atria followed by an irreversible depression. These effects were not prevented by atenolol, atropine or a combination of the two. In the presence of 25 microM lignocaine, the effects of venom on rat atria were reversible by washing. At 100 micrograms/ml, the venom transiently increased responses of vas deferens preparations to indirect stimulation, but had little effect on responses to noradrenaline, KCl, and ATP. In the presence of an alpha 1-adrenoceptor antagonist (prazosin) or a P2-purinergic receptor antagonist (suramin), the venom still significantly increased twitch height and responses to noradrenaline but not to KCl or ATP. The effect of the venom did not change after exposure to a combination of prazosin, suramin and tetrodotoxin. The venom (100 micrograms/ml) significantly decreased twitches to indirect and direct stimulation in chick biventer cervicis preparations. Responses to exogenously applied acetylcholine, carbachol and KCl were also decreased. Venom blocked the synaptosomal uptake of 3H-noradrenaline (IC50 = 5 micrograms/ml), and caused severe bradycardia in vivo. Some of the direct effects on muscle preparations are possibly due to the venom's phospholipase A2 activity.

The effect of the viper Cerastes cerastes cerastes venom and venom fractions on carbohydrate metabolism.

The effect of the viper Cerastes cerastes cerastes venom and venom fractions on carbohydrate metabolism. Toxicon 31, 791-801, 1993.--I.p. injection of a sublethal dose of Cerastes cerastes cerastes venom into white rats induced a marked hypoglycemia after 15 min. This hypoglycemia continued for at least 24 hr. Hypoglycemia was accompanied by a significant increase of liver and muscle glycogen at 15-30 min and 8 hr. Plasma lactate levels were significantly increased for most of the 24 hr test period, and was accompanied by a marked decrease of liver lactate levels. Levels of skeletal muscle lactate increased significantly. Viper venom significantly increased levels of plasma, liver and skeletal muscle pyruvate for most of the 24 hr test period. Cerastes cerastes cerastes venom was fractionated using gel filtration into six fractions. Each of the first four fractions caused a significant hypoglycemic effect at some point of the 6 hr test period, while fraction I also produced a hyperglycemia 30 min after administration. Fraction III, the only fraction to show a continuous hypoglycemic effect during the 6 hr test period, significantly increased plasma insulin levels 30 min after treatment. It is suggested that the hypoglycemia may be due to a direct effect of venom components on plasma insulin levels.

Alleviation of the heat load on lactating goats with the use of diuretics and drinking cool water.

The effect was studied of different heat loads connected with the application of diuretics and of 10 to 15 degrees C drinking water on the milk production and some related physiological parameters of 19 Egyptian Baladi goats under experimental conditions. The increase in heat stress increased the respiration rate, rectal temperature, and serum prolactin concentration significantly, while it significantly decreased the milk production, the content of alkaline, and acid phosphatases creatinine, urea, red blood cells, and haemoglobin concentration. The diuretic Thiameterine and cool drinking water under hot conditions improved the milk yield and had a positive effect on the physiological status of the animals, especially their blood composition. The higher mill production by the goats (14.7% in the experiment) is attributed to the increased feed uptake caused by the treatments.

Short term effects of animal venoms on the mitotic index of the duodenal mucosa of albino rats.

Short term administration of the venoms of the snakes Naja haje, Naja nigricollis, and Cerastes vipera and of the scorpion Leiurus quinquestriatus on the mitotic index of the duodenal mucosal cells of the white rat, Rattus rattus, has been studied. All the venoms increased the number of dividing cells of the duodenal mucosa significantly. Naja haje crude venom was fractionated into three fractions. Fraction I had no effect on the mitotic index whereas fractions II and III increased it significantly. Treatment of rats with Naja haje venom fractions II and III after blocking the histamine or the serotonin receptors did not affect the stimulatory action of the two venom fractions on the mitotic index, which it increased significantly. It was suggested that the venoms of Naja haje, Naja nigricollis, Cerastes vipera, and Leiurus quinquestriatus and Naja haje venom fractions possessed a mitogenic activity. Fraction II of Naja haje venom acted through both the muscarinic and adrenergic receptors while fraction III acted on the adrenergic ones.

Effect of a bradykinin potentiating fraction, from venom of the Egyptian scorpion, Buthus occitanus, on the ovaries and endometrium of mice.

An isolated fraction with bradykinin potentiating activity, from the venom of the Egyptian scorpion Buthus occitanus, was injected i.p. in female mice (35 days old). Five days after the injection of a single sublethal dose (1 micrograms/g), the number of primary multilaminar and secondary follicles of the ovaries was increased. Graafian follicles were observed in 50% of the treated mice but in none of the control mice. The number and size of the uterine glands and endometrium were increased in treated mice. Concomitantly, estradiol was increased in the circulating blood, while progesterone was within the normal limits. The enhancement of cellular growth by the isolated venom fraction with bradykinin potentiating activity, could be attributed to an enhancement of some growth factor(s) responsible for stimulating the ovarian follicles and uterus.

Proteins, lipids, lipoproteins and some enzyme characterizations of the venom extract from the centipede Scolopendra morsitans.

Some components of Scolopendra morsitans venom extract were characterized using disc gel electrophoresis and thin layer chromatography. Its protein component was separated into 13 anodal bands and a slowly moving cathodal band. The extract showed three slowly moving lipoprotein bands and the lipid components included phospholipids, cholesterol, free fatty acids, triglycerides, cholesterol esters and squalene. The enzymes esterase, acid and alkaline phosphatases and amino acid naphthylamidase were present in multiple forms. Acid phosphatase isoenzymes were of low activity.

The endocrine pancreas of a squamate reptile, the desert lizard (Chalcides ocellatus). A histological and immunocytochemical investigation.

The endocrine pancreas of the desert lizard (Chalcides ocellatus) was investigated histologically and immunocytochemically. The endocrine tissue was concentrated in the dorsal lobe, where it constituted about 7% of the total volume. In the ventral lobe the endocrine tissue formed approximately 1% of the total volume. Four endocrine cell types were observed in the pancreas of this species, namely insulin-, glucagon-, somatostatin- and pancreatic polypeptide (PP)-immunoreactive cells. The volume occupied by these cells was 1, 1, 0.6 and 0.3% of the total volume of the pancreas, respectively. Insulin-immunoreactive cells were located in the islet centre and comprised 3% of dorsal and 0.2% of the ventral lobe volume. Glucagon cells occurred at the islet periphery and amounted to 3 and 0.2% of the volume of the dorsal and ventral lobes, respectively. Somatostatin-immunoreactive cells were located at the islet periphery as well as in between the exocrine parenchyma. They constituted 1 and 0.2% of the volume of the dorsal and ventral lobes, respectively. PP-immunoreactive cells occurred mainly among the exocrine parenchyma as solitary cells. They formed only 0.03% of the volume of the dorsal lobe. The corresponding figure in the ventral lobe was 0.6%.

The effect of the plant hormone indole-3-acetic acid and chemically related compounds on the growth of mouse fibroblast 3T3 cells.

1. The effect of the plant hormone indole-3-acetic acid (IAA) and the chemically related compounds: serotonin, tryptophan, I. pyruvic, I. butyric, I. propionic and tryptamine on the growth of 3T3 cells has been studied. 2. Each of these compounds increases the cell number in a variable degree. The increase is related to the presence of the serum in the medium. 3. The kinetic relation between IAA, foetal calf serum and cell growth was studied. 4. It may be that IAA and related compounds affect the cell growth through adenylate cyclase and cAMP-cGMP systems.

Histological and immunohistochemical studies of the endocrine cells of the gastrointestinal mucosa of the toad (Bufo regularis).

Using histological and immunhistochemical techniques, nine endocrine cell types were observed in the mucosa of the gastrointestinal tract of the toad, Bufo regularis, viz. enterochromaffin, somatostatin, glucagon, pancreatic polypeptide (PP), secretin, gastric inhibitory peptide (GIP), gastrin-C-terminal pentapeptide (GTPP), neurotensin and bombesin cells. The enterochromaffin cells were distributed throughout the gastrointestinal tract except the rectum. Somatostatin, glucagon, PP, secretin, GIP and GTPP cells were observed both in the stomach and in the small intestine. Neurotensin cells were seen only in the ileum and bombesin cells only in the pyloric and antral parts of the stomach. Immunostaining of consecutive sections did not reveal more than one polypeptide hormone in any of these cell types. It is concluded from the present results that the toad gastrointestinal mucosa contains endocrine cell types that are more or less homologous to those in the mammal alimentary tract, though some of them exhibit a different topographic distribution.

Isozymes of amino acid naphthylamidase in human haematopoietic cell lines.

The occurrence of isozymes of the proteolytic enzyme amino acid naphthylamidase was investigated in a panel of 44 neoplastic and non-neoplastic haematopoietic cell lines by polyacrylamide gel electrophoresis. Two isozymes (A and C) were common for all lines, whereas different forms of a third isozyme with intermediate electrophoretic mobility (B) appeared in nine lines. Isozyme A seemed to be associated with cell proliferation and was not a marker for malignancy. The appearance of different B isozymes not present in normal peripheral blood lymphocytes, occurred in some Burkitt lymphoma lines and in two non-malignant lines maintained for a long time in culture. In three lines derived from myeloid leukaemia a variant of isozyme B seemed to be a marker for cell origin.