Do benzodiazepine receptors mediate the anticonflict action of pentobarbital?

The effects of the benzodiazepine antagonist CGS 8216 (2-phenylpyrazolo[4,3-c]quinoline-3(5H)-one) were examined in a thirsty rat conflict test in the presence and absence of pentobarbital. CGS 8216 (2.5-10 mg/kg i.p.) did not affect nonpunished responding, but doses of 5 and 10 mg/kg significantly reduced the rate of punished responding (i.e., the number of 3 second drinking episodes in a "shock" contingency). However, a dose of CGS 8216 which did not significantly alter punished responding (2.5 mg/kg) antagonized the anticonflict actions of pentobarbital. These observations suggest that while high doses of CGS 8216 may elicit an "anxiogenic" response in rodents, lower doses of CGS 8216 antagonize the anticonflict actions of a compound which has been shown to enhance benzodiazepine affinity in vitro. These data imply that the anticonflict actions of pentobarbital may be mediated through benzodiazepine receptors.     

GLOEOCOCCUS TETIMSPORUS SP. NOV. (TETRASPORALES,PALM ELL ACEAE), FROM COLORADO MOUNTAIN LAKES1

A new species, Gloeococcus tetrasporus sp. nov., collected from mountain lakes, is described from unialgal culture. Vegetative cells are ellipsoid and Chlamydomo nas–like, occur in tetrad complexes within the general colonial matrix, and exhibit slow, limited motility within the confines of the individual gelatinous matrices. The colonial matrix is amorphous and structureless, without a definite bounding layer. Colonies may reach several centimeters in size. Vegetative cells have a parietal cup–shaped chloroplast with a central–basal pyrenoid and a small, linear stigma, two contractile vacuoles, and two short flagella. Cell division is by eleutheroschisis in nonflagellate cells. After two divisions, four daughter cells arc formed within the expanded parent wall that will become incorporated into the colonial matrix. Zoospores are formed either from transformed vegetative cells or after cytokinesis. Zoospore flagella are two to three times the length of vegetative cell flagella. Rapid flagellar movement ruptures the sheath and liberates the zoospores. When zoospores settle, they secrete new sheaths, and divide twice to initiate new colonies. Sexual reproduction and formation of resistant spores were not observed.     

Human Adenovirus Type 2 but Not Adenovirus Type 12 Is Mutagenic at the Hypoxanthine Phosphoribosyltransferase Locus of Cloned Rat Liver Epithelial Cells

Using resistance to the base analog 8-azaguanine as a genetic marker, we showed that adenovirus type 2, but not adenovirus type 12, is mutagenic at the hypoxanthine phosphoribosyltransferase locus of cloned diploid rat liver epithelial cells. Adenovirus type 2 increased the frequency of 8-azaguanine-resistant colonies by up to ninefold over the spontaneous frequency, depending on expression time and virus dose.     

Buspirone: A potential atypical neuroleptic

Buspirone produces a dose-dependent but short-lived elevation in striatal dopamine (DA) metabolites in the rat. $\text{In}$$\text{vitro}$, buspirone possesses an affinity similar to sulpiride for DA receptors (3H-spiperone). A moderate affinity for α₁ receptors was also observed while buspirone was inactive at α₂, β, muscarinic and serotonin₂ receptors. This pharmacological profile as well as previous behavioral data indicate that buspirone may be a potential “atypical” neuroleptic.     

Multiple Forms of Choline-O-Acetyltransferase in Mouse and Rat Brain: Solubilization and Characterization

Three forms of acetyl coenzyme A: choline-O-acetyltransferase (EC 2.3.1.6, ChAT) have been isolated from mouse and rat forebrain synaptosomes with a 100 mM sodium phosphate (NaP) buffer of pH 7.4, a high-salt solution (500 mM NaCl), and a 2% Triton DN-65 solution, respectively. The Triton-solubilized form of ChAT differed from the other two forms in its capacity to acetylate homocholine, its pH profile, and its sensitivity to denaturation. NaCl-solubilized ChAT could be distinguished from the other two forms with respect to pH profile, sensitivity to inhibition by 4-(1-naphthylvinyl) pyridine (in the presence of Triton), and apparent Km value for choline acetylation. The caudate and putamen of rat brain contained the highest amount of ChAT activity, based on tissue wet weight, and the cerebellum contained the least of the brain regions examined; only the cerebellum had more membrane-bound than soluble ChAT. Septal lesion reduced ChAT activity in the NaP- and Triton-solubilized fractions prepared from hippocampus by 68% and 64%, respectively, whereas it reduced the activity of the NaCl-solubilized fraction by only 21%. These results suggest that three different forms of ChAT may exist in both mouse and rat brain.     

A pterosaurian notarium from the Lower Cretaceous of Brazil

A pterosaur vertebral column consisting of the last cervical vertebra, the first five dorsals fused to a notarium, and the following four dorsal vertebrae, is figured and described from the Aptian Santana Formation of the Chapada do Araripe in northeastern Brazil. The specimen is tentatively referred toSantanadactylus brasilensis de Buisonjé. It is the best preserved and most complete pterosaurian notarium known. Its functional significance is discussed.     

Temperature modification of respiratory metabolism and caloric intake of Pandalus borealis (Krøyer) first zoeae

Oxygen consumption rates (Q_O2) of laboratory reared stage one zoeae of Pandalus borealis (Krøyer) at 1.5, 3, 4.5, 6, and 9°C were 1.5, 2.2, 2.6, 3.6 and 4.1μ O₂ · mg^?1 · h^?1, respectively. These values of Q_O2 correspond to 0.26, 0.38, 0.44, 0.60, and 0.70 μl O₂ · individual^?1 · h^?1. At 10.5 °C oxygen consumption rates decreased suggesting thermally induced respiratory stress.The equation log₁₀Q_O2 = 0.55 log₁₀T°C + 0.086 describes the relationship between Q_O2 (μl O₂ · mg^?1 · h^?1) and sea-water temperature between 1.5 and 9°C. Corresponding values of Q_O2 for an individual (μl O₂ · h^?1) exhibited the relationship log₁₀Q_O2 = 0.55 log₁₀T°C ?0.686.The minimum daily metabolic caloric requirements for an individual zoea ranged from 0.04 at 3 °C to 0.07 calories per day at 8 °C. The number of calories ingested daily ranged from 0.4 to 0.5 at 3 to 8 °C.     

Evolution of epitopes on human and nonhuman primate lymphocyte cell surface antigens

The T- and B-cell surface polypeptides detected by an international workshop panel of 100 mouse monoclonal antibodies (M.Ab) were biochemically defined by radioimmunoprecipitation. Eight T-cell-associated molecules and eight B-cell-associated molecules were identified by multiple antibodies in the panel. Clusters of antibodies specific for the same polypeptide were then compared for their reactivity against peripheral blood mononuclear cells (PBMC) from 11 nonhuman primate species. All the major T- and B-cell antigens present in humans were also expressed in some nonhuman primates. M.Ab to the same antigen were found to react with distinct epitope groups that differed in their phylogenetic distribution. Some epitopes were highly conserved, while other epitopes on the same molecule were only expressed in hominoids and were not detected in old world and new world monkeys. Our detailed analysis of the phylogeny of 37 T-cell antigen epitopes on ten different molecules revealed there was no clear correspondence between the number of epitopes shared and evolutionary distance. Rather the data suggest that parallelism with back mutation may be a common mechanism in the evolution of T-cell antigens. The data also show that the tissue distribution of T-cell antigens can differ between primate species; for example, M.Ab to human Tp45 Tla-Qa-like antigens that did not react with human PBMC did react with PBMC from new world monkeys.