Heterogeneity of Benzodiazepine Receptors: Experimental Differences Between [3H]Flunitrazepam and [3H]Ethyl-β-carboline-3-carboxylate Binding Sites in Rat Brain Membranes

Abstract: This study was designed to analyze possible differences in the binding of [³H]flunitrazepam ([³H]FNZP) and [³H]ethyl - β - carboline - 3 - carboxylate ([³H]β-CCE), to rat brain membranes, in various experimental conditions. In cerebral cortex, hippocampus, cerebellum, and orain stem the number of binding sites for [³H]β-CCE was higher than for [³H]FNZP; both were displaced by clonazepam. Until the 7th day of postnatal brain development the numbers of [³H]FNZP and [³H]β-CCE sites were equivalent; but later on, the β-carboline sites increased to a higher level. Noradrenergic denervation by 6-hydroxydopamine was followed in the hippocampal formation. Already after 2 days, there was a decrease in [³H]FNZP sites, which reached 70% of control after 14 days. Similar results were obtained with DSP-4 denervation. This change was only in B_max and not in K_D, In contrast, the [³H]β-CCE sites did not change with denervation. Neonatal injection of l - 2,4,5 - trihydroxyphenylalamine or DSP-4 produced in the adult a decrease in [³H]FNZP sites in the cerebral cortex, in parallel with the noradrenergic denervation. On the other hand, there was an increase in the cerebellum and brain stem, in correspondence with the hyperinnervation by sprouting. In these rats, the number of sites for [³H]β-CCE did not change in the different brain regions. With 0.1% Triton X-100, applied to synaptosomal membranes, [³H]FNZP binding was reduced by 35%, while that of [³H]β-CCE was not significantly changed. These results suggest that there is heterogeneity of binding sites for benzodiazepine receptors in rat brain. A tentative interpretation of the experiments involving noradrenergic denervation and hyperinnervation, as well as those with Triton X-100, is that [³H]FNZP binds to pre- and postsynaptic receptors, while [³H]β-CCE binds mainly to postsynaptic benzodiazepine receptors.     

Population growth in random environments

This paper reviews some recent advances in single population stochastic differential equation growth models. They are a natural way to model population growth in a randomly varying environment. The question of which calculus, Itô or Stratonovich, is preferable is addressed. The two calculi coincide when the noise term is linear, if we take into account the differences in the interpretation of the parameters. This clarifies, among other things, the controversy on the theory of niche limiting similarity proposed by May and MacArthur. The effects of correlations in the environmental fluctuations and statistical methods for estimating parameters and for prediction based on a single population trajectory are mentioned. Applications to fisheries, wildlife management and particularly to environmental impact assessment are now becoming possible and are proposed in this paper.     

The taxonomy of the family Paramphistomidae Fischoeder, 1901 with special reference to the morphology of species occurring in ruminants. III. Revision of the genus Calicophoron Näsmark, 1937

Summary The genus Calicophoron N?smark, 1937 is redefined. Only the following species originally assigned by N?smark to the genus are considered valid: C. calicophorum (Fischoeder, 1901) N?smark, 1937 (type species); C. papillosum (Stiles & Goldberger, 1910) N?smark, 1937; and C. raja N?smark, 1937. The following species previously assigned to the genus Paramphistomum Fischoeder, 1901 are considered valid but moved to the genus Calicophoron N?smark, 1937 in new combinations: C. bothriophoron (Braun, 1892); C. microbothrium (Fischoeder, 1901); C. papilligerum (Stiles & Goldberger, 1910); C. clavula (N?smark, 1937); C. microbothrioides (Price & McIntosh, 1944); C. sukari (Dinnik, 1954); C. phillerouxi (Dinnik, 1961); C. daubneyi (Dinnik, 1962) and C. sukumum (Dinnik, 1964). The genus Bothriophoron (Stiles & Goldberger, 1910) Grétillat 1958 is synoymized with Calicophoron N?smark, 1937. Paramphistomum crassum Stiles & Goldberger, 1910, P. cauliorchis Stiles & Goldberger, 1910, P. ijimai Fukui, 1922, P. (Cauliorchis) skrjabini Popova, 1937, P. erschovi Davydova, 1959, Calicophoron orientalis Mukherjee, 1966, C. wuchengense Wang, 1979 and Cotylophoron skrjabini Mitskevich, 1958 in part are considered synonyms of Calicophoron calicophorum (Fischoeder, 1901) N?smark, 1937. C. zhejiangense Wang, 1979 is regarded a synonym of C. papillosum (Stiles & Goldberger, 1910) N?smark, 1937. P. vangrembergeni Van Strydonck, 1970 and P. togolense Albaret, Bayssade-Dufour, Guilhon, Kulo & Picot, 1978 are considered synonyms of Calicophoron phillerouxi (Dinnik, 1961) n. comb. and Ceylonocotyle petrovi Davydova, 1961 is synonymized with Calicophoron microbothrioides (Price & McIntosh, 1944) n. comb. The species considered valid under the genus are redescribed and illustrated and scanning electron photomicrographs of the tegumental surfaces of some species are provided. A key to the species is given. Part of a thesis approved by the University of London for the award of the Ph.D. degree.     

Inactivation of 1,6-Diphosphatase by Glucose in Yeast

Fructose-1,6-diphosphatase was derepressed in Saccharomyces cerevisiae by incubation in media containing non-sugar carbon sources. Addition of glucose to a derepressed culture led to a rapid loss of the measurable activity of the enzyme. Fructose and mannose also produced inactivation, but 2-deoxyglucose was ineffective. Experiments with cycloheximide indicated that the inactivation does not require protein synthesis. It was also shown that the process is not energy-dependent. The reappearance of the enzyme was dependent on an energy source and was prevented by cycloheximide. These results suggest that fructose diphosphatase inactivation is irreversible and that reappearance of enzyme activity implies de novo synthesis. Screening of different genera of yeasts has shown that the inactivation of fructose diphosphatase is a relatively widespread phenomenon.     

Periodate-induced lymphocyte transformation. 3. Effects of temperature and pH

The optimum conditions for sodium periodate induced lymphocyte transformation occur at low concentrations of NaIO₄, low temperature, pH between 6 and 7.5, and with short periods of exposure to the NaIO₄. Exposures for prolonged times at elevated temperatures or to NaIO₄ at pH above 7.5 result in diminished responses. The finding of maximum lymphocyte response under these conditions is compatible with the proposal that the triggering event in NaIO₄ transformation of lymphocytes is the oxidation and cleavage of the two terminal carbon atoms of sialic acid. Exposure of lymphocytes to NaIO₄ under conditions of higher temperature, higher pH or longer exposure times does not significantly reduce their ability to respond to phytohemagglutinin (PHA) or pokeweed mitogen (PWM). This finding suggests that these mitogens have different target sites from that of NaIO₄ or that they are acting on different populations of lymphocytes.     

Discrimination between groups of chromosomes and individual chromosomes in the normal human karyotype

The karyotypes of 200 normal individuals are examined in a study designed to investigate the extent to which the cytologist's classification of chromosomes into the A–G autosomal groups and identification of individual chromosomes are reflected in the values of measurements made on these chromosomes. The statistical technique of discriminant function analysis is employed to obtain linear functions of the chromosomal measurements which may be used to classify and identify chromosomes. The results of the study indicate that while chromosomes can be grouped with a reasonably high probability of success using measurements alone, identification of individual chromosomes is somewhat more difficult.     

POLYMORPHISM IN THE DESMID XANTHIDIUM REGULARE AND ITS TAXONOMIC IMPLICATIONS

This paper refers to a case of polymorphism in the desmid genus Xanthidium Ehr. It is based on material from Lake Dais Irmaios, the main body of water in the Zoological and Botanical Garden in Recife, Pernambuco, northeastern Brazil, collected at 4 different times of the year during 1967 and 1968. A detailed examination of almost 1300 specimens showed an enormous variety in form of Xanthidium regulare Nordst., X. fragile Borge, and X. pseudoregulare Borge, thus allowing the authors to draw the following conclusions: (1) the name X. regulare Nordst. should be retained until further and more detailed studies on form variation within the species are available; (2) the names X. regulare Nordst. var. asteptum Nordst. in Borge, X. regulare Nordst. var. sexangulare Grönbl., X. regulare Nordst. var. sexangulare Grönbl. f. robustior Grönbl., X. fragile Borge, X. fragile Borge forma, and X. fragile Borge var. depauperatum Borge should be considered synonymous, all referring to a single variety of X. regulare Nordst., var. asteptum Nordst. in Borge emend. C. Bic. & L. M. Carv.; (3) X. pseudoregulare Borge must be treated as a variety of X. regulare Nordst. and must be called X. regulare Nordst. var. pseudoregulare (Barge) C. Bic. & L. M. Carv. Finally, a key is given to the 3 varieties of X. regulare Nordst. proposed in the present paper.     

Action spectrum for polarotropism of the germ tube of the liverwort Sphaerocarpos Donnellii aust.

Summary A series of dose response curves was worked out in the polarotropically active blue and UV spectral region. These dose response curves show changes in slope as a function of wavelength. In blue the slope values are higher than in UV. As a consequence, both the relative height of the peaks in blue and UV and the fine characteristics in blue of the action spectrum calculated on the basis of these dose response curves change decisively with different response levels taken for calculation. Therefore no decision can be made as to what photoreceptor(s) might be involved. Though at medium response levels the action spectra show similarity with action spectra of other blue-UV-mediated photoresponses, which generally are believed as being indicative of some flavin.