In vivo labelling of the mouse brain 5-hydroxytryptamine1A receptor with the novel selective antagonist 3H-NAD-299

The in vivo labelling of 5-hydroxytryptamine (5-HT)1A receptors in the mouse brain was studied with the novel selective 5-HT1A receptor antagonist, NAD-299 ((R)-3-N,N-dicyclobutylamino-8-fluoro-3,4-dihydro-2H-1-benzopyran- 5-carboxamide hydrogen (2R,3R)-tartrate monohydrate). 3H-NAD-299 was injected in a tail vein and the radioactivity in various brain regions was determined. More than 90% of the radioactivity in hippocampus, 15 min after the injection, was intact NAD-299. At this time the amount of 3H-NAD-299 was highest in hippocampus followed by frontal cortex, mesencephalon, hypothalamus, striatum and cerebellum. The specific accumulation of radioactivity (after subtracting cerebellum values) in frontal cortex and hippocampus was maximal 10 to 30 min after the injection and had almost disappeared after 2 h. Saturation kinetics derived Bmax (pmol/g wet weight tissue) values of 19.6+/-2.0 in frontal cortex and 38.0+/-3.5 in hippocampus. The apparent Kd values expressed in nmol/kg 3H-NAD-299 injected, were 12.3+/-2.2 in frontal cortex and 20.3+/-3.1 in hippocampus. The 5-HT1A receptor antagonist, WAY-100,635 competitively inhibited the specific accumulation of 3H-NAD-299 and was about equipotent with unlabelled NAD-299 with ED50 values of 20-30 nmol/kg s.c. These compounds were about 10 times more potent than the 5-HT1A receptor antagonists, p-MPPI and NDL-249 and 100 times more potent than (S)-UH-301. 5-HT1A receptor agonists, e.g. 8-OH-DPAT and flesinoxan and partial agonists, e.g. pindolol, buspirone and ipsapirone had low potency in this in vivo assay. Spiperone and methiothepin inhibited the 3H-NAD-299 accumulation at 10 micromol/kg s.c. The alpha1-adrenoceptor antagonist, prazosin at 2 micromol/kg s.c. increased significantly the specific accumulation of 3H-NAD-299. Pretreatment of the mice with the non-selective, irreversible receptor antagonist, EEDQ produced a dose related long-lasting decrease in the accumulation of 3H-NAD-299. It is concluded that NAD-299 is a very suitable ligand for studies of 5-HT1A receptors in the brain in vivo.     

Epithalamin effects on carbohydrate metabolism and cardiovascular system in patients with non-insulin dependent diabetes mellitus

Epithelamine made in Russia (Samson, St. Petersburg) was tried for effects on carbohydrate metabolism and cardiovascular system in 33 patients with non-insulin-dependent diabetes mellitus (NIDDM). Adjuvant use of epithelamine in combined treatment of NIDDM promoted a stable compensation of carbohydrate metabolism, lowering of glycosylated hemoglobin, immunoreactive insulin. There was also a moderate hypotensive effect and improvement of left ventricular diastolic function.     

Functional complementation by electroporation of human BACs into mammalian fibroblast cells

Bacterial Artificial Chromosomes (BACs) have been used to complement a metabolic defect and to transfer a drug resistance marker into mammalian cells by electroporation. The selectable markers are stable and the recipient cells have BAC DNA integrated into the chromosomes as shown by fluorescent in situ hybridization, PCR and Southern hybridization.     

The exotoxin of Bacillus thuringiensis: a new C-mitotic agent

Thuringiensin A, an exotoxin from Bacillus thuringiensis, a constituent of the microbial insectide thuricide has been found to inhibit mitotic spindle, condense and scatter chromosomes. It may therefore be a promizing tool in future cell biological studies.