Stimulation of dopamine synthesis and release by morphine and D-Ala2-D-Leu5-enkephalin in the mouse striatum in vivo

The effects of opiates on dopamine (DA) release and synthesis were assessed in the mouse striatum $\text{in vivo}$ by simultaneously measuring 3,4-dihydroxyphenylalanine (DOPA) and 3,4-dihydroxyphenylacetic acid (DOPAC) levels after inhibition of aromatic amino acid decarboxylase. This method was developed to assess stimulus-coupled changes in DA synthesis and release. Peripheral injections of morphine and intraventrcular injections of D-Ala²-Leu⁵-enkephalin elevated DOPAC levels, indicating that “opiates” stimulated DA release. Concomitantly, the rate of DA synthesis was increased. The effects were dose-dependent, saturable and antagonized by naloxone. When morphine and the enkephalin analog were given together in saturating doses, the effects of the two agents were not additive. Thus, the involvement of different receptors in the mediation of the effects of morphine and enkephalins could not be demonstrated.     

Endogenous opiates inhibit gastric acid secretion induced by central administration of Thyrotropin-Releasing Hormone (TRH)

Thyrotropin-releasing hormone (TRH) administered intraventricularly (ICV) to rats causes a dose-dependent increase in gastric acid secretion over a range of 0.01 μg to 10 μg in the pyloris ligated rat. The maximum increase in gastric acid secretion occurs in the first hour. This effect of TRH is not mediated by its metabolites, histidyl-proline diketopiperazine or pyroglutamyl-histidyl-proline (acid TRH). β-endorphin, D-alanine-methionine-enkephalin and the leucine-enkephalin precursor, dynorphin, all inhibit TRH-induced gastric acid secretion. Bombesin, which reduces basal gastric acid secretion had no effect on TRH-induced secretion.     

Pyruvate dehydrogenase complex from germinating castor bean endosperm

Subcellular organelles from castor bean (Ricinus communis) endosperm were isolated on discontinuous sucrose gradients from germinating seeds which were 1 to 7 days postimbibition. Marker enzyme activities of the organelles were measured (fumarase, catalase, and triose phosphate isomerase) and the homogeneity of the organelle fractions was examined by electron microscopy. Pyruvate dehydrogenase complex activity was measured only in the mitochondrial fraction and attempts to activate or release the enzyme from the proplastid were not successful. A pathway is proposed for the most efficient use of endosperm carbon for de novo fatty acid biosynthesis that does not require the presence of the pyruvate dehydrogenase complex in the proplastid to provide acetyl-coenzymeA.     

A qualitative difference in plasma renin activity in dahl rats susceptible or resistant to salt-induced hypertension

Plasma renin activity (PRA) was studied in the rats bred by Dahl for susceptibility (S-strain) or resistance (R-strain) to salt (NaCl) induced hypertension. The pH curves for PRA had different shapes. The difference in shape of the pH curves was reflected in the ratio of PRA pH 8/PRA pH 6.5. This ratio was shown to be characteristic of the strain and to be independent of changes in absolute PRA level induced by variation in dietary NaCl. The ratio of PRA pH 8/PRA pH 6.5 was also different between strains in weanling as well as adult rats. The underlying cause for the strain difference in the effect of pH on PRA is unknown, but may involve molecular differences between strains in either renin or renin substrate.     

The influence of coal ash and thermal discharges upon the distribution and bioaccumulation of aquatic invertebrates

The distribution, density and uptake of twenty elements by aquatic invertebrates inhabiting a drainage system, that received excessive coal ash effluent (275 JTU of turbidity) at one end and thermal loading (44.5°C) at the other end, was studied for 15 months. The ash settling basin filled during the first eight months of sampling which resulted in the release of ash effluent directly into the receiving system. Density of invertebrates was lowest in the 300 m stream between the ash basin and swamp and highest 1200 m beyond the stream-swamp confluence where ash influence was minimal. Invertebrate density was lowest in the stations where turbidity from ash effluent was greatest. The most tolerant invertebrates to coal ash stress were odonates (Libellula sp. and Enallagma sp.), crayfish (Procambarus sp.), amphipods (Gammarus sp.) and gastropods (Physa. sp.), and midges (Chironomidae) when the basin was filling. During the period of ash overflow, all groups were either reduced in numbers or absent. In the thermally stressed station, Libellula sp. was the predominant invertebrate sampled when water temperature ranged from 25.5–45.5°C (257-1=28.7°C) all aquatic invertebrates were limited in numbers and density when temperature exceeded the lower and upper ranges of 10.0–38.0°C.This research was supported by AEC Contract AT (38-1-824)This research was supported by AEC Contract AT (38-1-824)     

Host range temperature-sensitive mutants of herpes simplex virus type 2.

Two small-plaque mutants of herpes simplex virus type 2 (HSV-2) (strain 333), whose growth at 39 C was blocked in certain cell types (cell-dependent temperature sensitivity), were compared compared with parental virus in a number of biological assays. One mutant (no. 69) was found to produce a large number of morphologically normal, but noninfectious, particles; under nonpermissive conditions, these mutant particles were able to interfere with the replication of wild-type HSV-2. The other mutant (no. 74), which is known to belong to a different complementation group, appeared to direct little virus DNA synthesis, even at the permissive temperature. Progeny production and virus DNA synthesis in cells infected by mutant 74 were delayed in comparison with wild-type virus-infected cells. Both mutants were found to be more sensitive to UV irradiation than the parental virus; this was especially marked in the case of mutant 74. Moreover, this mutant was found to have a high transforming efficiency at much lower doses of irradiation than those needed to abolish the cytopathic effect of wildtype HSV-2.     

Herpes simplex virus DNA in transformed cells: sequence complexity in five hamster cell lines and one derived hamster tumor.

Analyses of the hybridization kinetics of labeled herpes simplex virus 2 (HSV-2) DNA with DNA from five hamster cell lines transformed by UV light-irradiated HSV-2 revealed the following. (i) Viral DNA sequences were detected in all five cell lines tested. (ii) None of the cell lines contained the full complement of HSV-2 DNA. (iii) The amount of viral DNA present in the cells varied in different transformed cell lines and ranged from 8 to 32% of the HSV-2 DNA genome in 1 to 3 copies/cell. (iv) Two parallel passages of the same cell line (333-2-29) differed in the amount of viral DNA they contained. We also compared the viral DNA sequences present in (i) one transformed cell line (333-8-9) propagated serially in culture for 80 passages, (ii) a tumor produced by inoculation of a newborn hamster with the 333-8-9 cells, and (iii) a cell line derived from a hamster tumor as above and propagated in culture for 32 passages. The results show that viral DNA present in the hamster tumor and in the cells derived from the tumor had a lower sequence complexity than that present in the original serially passaged 333-8-9 cell line.     

The development by cytomegalovirus-infected cells of binding affinity for normal human immunoglobulin.

After infection with human cytomegalovirus (CMV), cells develop an affinity for normal human immunoglobulin G (IgG). This was demonstrated using 125iodine-labeled purified IgG. It was further demonstrated that the immunoglobulin molecule binds to CMV-infected cells via its Fc portion, and competition for binding to infected cells occurred between purified preparations of human IgG and the Fc fragment of human IgG. Whole sera from individuals with or without a high titer of anti-CMV antibody were labeled with 125iodine and it was demonstrated that serum from individuals with no anti-CMV antibody had an affinity for CMV-infected cells which probably reflected binding of IgG via its Fc fragment. The possible significance of these results in immunologic studies of human CMV is considered.     

Isolation and preliminary characterization of temperature-sensitive mutants of measles virus.

Twenty-four genetically stable temperature-sensitive mutants of measles virus were isolated after mutangenesis by 5-azacytidine, 5 fluorouracil, or proflavine. The restricted replication of all mutants at 39 C was blocked subsequent to cell penetration and could not be attributed to heat inactivation of virus infectivity. Complementation analysis was made possible through the use of poly-L-ornithine. The members of one complementation group exhibited wild-type RNA synthesis at the nonpermissive temperature and induced the synthesis of virus antigens. These mutants were found defective in both hemolysin antigen synthesis and cell fusion "from within," supporting the unitary hypothesis for these functions. The members of the other two complementation groups synthesized neither virion RNA nor detectable virus antigens at the nonpermissive temperature.