Swim Stress Increases the Potency of Glycine at the N-Methyl-d-Aspartate Receptor Complex

Abstract: We have previously demonstrated that chronic administration of antidepressants results in a reduction in the potency of glycine to displace 5,7-[³H]dichlorokynurenic acid (5,7-[³H]-DCKA) from the strychnine-insensitive glycine recognition site of the NMDA receptor complex. We now report that exposure of rats to the forced swim test results in a 56% increase in the potency of glycine to displace 5,7-[³H]DCKA from frontal cortical homogenates. These data are consistent with the hypothesis that the forced swim test, a preclinical screen sensitive to acute administration of antidepressant drugs and NMDA receptor antagonists, also results in adaptation of the NMDA receptor complex. Moreover, these data lend further support to the hypothesis that glutamatergic pathways are involved in the neurobiological response to stress and, potentially, in the pathophysiology of depression.     

Hyperphagia and hyperdipsia after locus coeruleus lesions in the stumptailed monkey.

Bilateral lesions of the nucleus locus coeruleus in 7 female stumptail monkeys were followed by long lasting hyperphagia and hyperdipsia. The percentage increase in weight at five weeks after lesioning correlated highly with 3-methoxy-4-hydroxy-phenethylene glycol (MHPG) concentration in the cerebral cortex. This relationship suggests that the effects are due to the locus coeruleus system and are not the result of variable destruction of the ventral noradrenergic or adjacent non-noradrenergic pathways.     

The ANF-C receptor is not linked to adenylyl cyclase inhibition in bovine pulmonary artery endothelial cells.

The possible inhibition of adenylyl cyclase activity by atrial peptides selective for the ANF-C receptor was investigated in bovine pulmonary artery endothelial cells. In these cells isoprenaline, guanine nucleotide and forskolin dose-dependently increased activity over basal levels. In the presence of rANF(99-126), these dose-dependent increases were not reduced, nor were they affected by the ANF-C receptor selective analogue C-ANF(102-121). Furthermore, the selective analogues rANF(103-123) and des[Cys105,Cys121]rANF104-126 had no effect on basal or stimulated adenylyl cyclase activity. It can be concluded that ANF-C receptors are not linked to inhibition of adenylyl cyclase in these cells.     

Rhizobium leguminosarum exoB mutants are deficient in the synthesis of UDP-glucose 4'-epimerase

Rhizobium leguminosarum bv. viciae Exo- mutant strains RBL5523,exo7::Tn5,RBL5523,exo8::Tn5 and RBL5523,exo52::Tn5 are affected in nodulation and in the syntheses of lipopolysaccharide, capsular polysaccharide, and exocellular polysaccharide. These mutants were complemented for nodulation and for the syntheses of these polysaccharides by plasmid pMP2603. The gene in which these mutants are defective is functionally homologous to the exoB gene of Rhizobium meliloti. The repeating unit of the residual amounts of EPS still made by the exoB mutants of R. leguminosarum bv. viciae lacks galactose and the substituents attached to it. The R. leguminosarum bv. viciae and R. meliloti exoB mutants fail to synthesize active UDP-glucose 4'-epimerase.     

Vascular atrial natriuretic factor receptor subtypes are not independently regulated by atrial peptides

The regulation of the atrial natriuretic factor (ANF) receptor system in cultured rat vascular smooth muscle cells (RVSMC) was examined following long term pretreatment of these cells with rANF99-126 or with any one of a series of truncated and ring-deleted analogs. The latter analogs are reported to bind selectively the ANF-C or clearance receptor. Initial competition binding studies revealed that all analogs examined showed comparable apparent receptor binding affinities (Ki values did not differ by more than 10-fold). In contrast, the extent of interaction of the ANF analogs with the receptor pool coupled to particulate guanylate cyclase (the ANF-B receptor) was much more variable, with some ligands failing to stimulate cGMP production or particulate guanylate cyclase over the concentrations tested. Pretreatment of cells for 24 h with rANF99-126 or any of the truncated analogs that interact with the ANF-B receptor caused a dose- and time-dependent decrease in the number of ANF binding sites (99% of which are uncoupled in RVSMC) without any change in affinity. Examination of the binding activity following pretreatment of the cells with ANF suggested that the observed reduction in 125I-rANF99-126 binding capacity was not because of the retention of the peptide on its receptor. Furthermore, this down-regulation was associated with desensitization of particulate guanylate cyclase resulting in a decreased responsiveness of intracellular cGMP accumulation to ANF. In contrast, however, analogs selective for the ANF-C receptor pool failed to cause down-regulation or desensitization. These findings suggest that ANF-C receptors in RVSMC are not independently down-regulated by selective ligands but that nonselective analogs that down-regulate and desensitize the ANF-B receptor system can by some cooperative mechanism reduce the size of the predominant ANF-C receptor pool in these cells.     

Plasma amine oxidase activity in 136 normal rhesus monkeys: relationships between enzyme activity and age, sex and genetic factors.

Normative data on plasma amine oxidase activity were obtained for four primate species, M. mulatta, M. arctoides, C. aethiops and H. sapiens. Significant between-species differences in activity were observed. In a large sample of M. mulatta, no significant relationship between age and plasma amine oxidase activity was observed, but adult males had significantly higher enzyme activities than adult females.     

Dredge and fill regulatory constraints in meeting the ecological goals of restoration projects

Regulators face the problem of ensuring that wetland functions that are lost due to permitting actions are restored via mitigation of those impacts. While there has been considerable study of wetland function, little of it has been directed toward the practical assessment of mitigation success. Development of quantitatively based rapid assessment methods would provide valuable assistance to the regulatory community. Regional and local goal setting, including a determination of whether strict in-kind restoration or restoration of habitat balance is preferable, is needed to ensure that the ecological health of the area is restored to the greatest extent possible.     

Some sampling considerations in the quantitation of monkey behavior under field and captive conditions

Observations of monkey behavior were made on free-ranging and corral-enclosedMacaca mulatta. Two sampling techniques were used: focal animal and group observations. Group observations measured frequencies of social behavior whereas focal observations used time samples which estimated durations of social and nonsocial activities as well as frequencies of social behavior. Analysis of concordance within and between sampling techniques revealed that short duration focal time samples provide a reliable estimate of total frequencies of social behaviors derived using group observations and furthermore, allows the recording of important nonsocial activities not easily recorded in terms of frequencies. Focal time sampling is advantageous for certain types of studies where the equal distribution of observation time between individuals is important, particularly in the field where visibility is often limited and individuals can only be observed continuously for short periods of time. This work was supported by grants from the H. F. Guggenheim Foundation, Dr.H. C. Robinson, Jr., and USPHS grants MH 24607 and MH 25642.     

Assessing Insecticide Hazard to Bumble Bees Foraging on Flowering Weeds in Treated Lawns

Maintaining bee-friendly habitats in cities and suburbs can help conserve the vital pollination services of declining bee populations. Despite label precautions not to apply them to blooming plants, neonicotinoids and other residual systemic insecticides may be applied for preventive control of lawn insect pests when spring-flowering weeds are present. Dietary exposure to neonicotinoids adversely affects bees, but the extent of hazard from field usage is controversial. We exposed colonies of the bumble bee Bombus impatiens to turf with blooming white clover that had been treated with clothianidin, a neonicotinoid, or with chlorantraniliprole, the first anthranilic diamide labeled for use on lawns. The sprays were applied at label rate and lightly irrigated. After residues had dried, colonies were confined to forage for six days, and then moved to a non-treated rural site to openly forage and develop. Colonies exposed to clothianidin-treated weedy turf had delayed weight gain and produced no new queens whereas those exposed to chlorantraniliprole-treated plots developed normally compared with controls. Neither bumble bees nor honey bees avoided foraging on treated white clover in open plots. Nectar from clover blooms directly contaminated by spray residues contained 171±44 ppb clothianidin. Notably, neither insecticide adversely impacted bee colonies confined on the treated turf after it had been mown to remove clover blooms present at the time of treatment, and new blooms had formed. Our results validate EPA label precautionary statements not to apply neonicotinoids to blooming nectar-producing plants if bees may visit the treatment area. Whatever systemic hazard through lawn weeds they may pose appears transitory, however, and direct hazard can be mitigated by adhering to label precautions, or if blooms inadvertently are contaminated, by mowing to remove them. Chlorantraniliprole usage on lawns appears non-hazardous to bumble bees.