Brief exposure to 60 Hz magnetic fields improves sexually dimorphic spatial learning performance in the meadow vole, Microtus pennsylvanicus

1993 ◽  
Vol 173 (2) ◽  
Author(s):  
M. Kavaliers ◽  
L.A. Eckel ◽  
K.-P. Ossenkopp
Keyword(s):  
Magnetic Fields ◽  
Spatial Learning ◽  
Microtus Pennsylvanicus ◽  
Learning Performance ◽  
Meadow Vole ◽  
Sexually Dimorphic

Sexually dimorphic spatial learning in meadow voles Microtus pennsylvanicus and deer mice Peromyscus maniculatus.

1996 ◽  
Vol 199 (1) ◽  
pp. 195-200 ◽  
Author(s):  
L A Galea ◽  
M Kavaliers ◽  
K P Ossenkopp
Keyword(s):  
Breeding Season ◽  
Spatial Learning ◽  
Water Maze ◽  
Microtus Pennsylvanicus ◽  
Group Differences ◽  
Deer Mice ◽  
Sexually Dimorphic ◽  
Meadow Voles ◽  
Spatial Performance ◽  
Males And Females

A number of studies examining developmental, neural and hormonal aspects of sexually dimorphic spatial learning (Morris water-maze) in meadow voles (Microtus pennsylvanicus) and deer mice (Peromyscus maniculatus) are described. We found that, in adult deer mice, female spatial performance decreased during the breeding season relative to the non-breeding season, whereas the reverse pattern was observed in male performance. There was a sex difference favouring males in spatial learning during the breeding season, but not during the non-breeding season. In adult meadow voles, females with low levels of oestradiol and males performed better in the water-maze than females with high levels of oestradiol. Postweaning voles (20 and 25 days after birth) acquired the water-maze task more quickly than preweaning voles (day 10). No sex difference in water-maze performance was evident at any of these juvenile ages. When these same voles were tested again as adults to investigate retention and re-acquisition of the water-maze, both males and females from male-biased litters re-acquired the task better than males and females from female-biased litters. Together, the results of these studies indicate that sexually dimorphic spatial ability is dependent on the organization (in utero) and activational effects of gonadal hormones. These studies provide the first demonstration of the influence of natural changes in reproductive status on spatial learning of deer mice and meadow voles. The results also demonstrate that spatial performance of males and females is differentially affected by changes in reproductive status and that group differences in the laboratory are associated with group differences in space utilization in the wild. These findings help to clarify previous apparently contradictory findings about sex differences in spatial ability.

Winter coexistence of voles in spruce forest: relevance of seasonal changes in aggression

1975 ◽  
Vol 53 (8) ◽  
pp. 1004-1011 ◽  
Author(s):  
Brian N. Turner ◽  
Michael R. Perrin ◽  
Stuart L. Iverson
Keyword(s):  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Breeding Period ◽  
Spruce Forest ◽  
Vole Population ◽  
Reproductive Condition ◽  
Interspecific Aggression ◽  
Meadow Voles ◽  
Nonbreeding Season ◽  
Short Period

Beginning in November 1973, numerous meadow voles (Microtus pennsylvanicus) moved onto a spruce forest grid occupied by red-backed voles (Clethrionomys gapperi). A resident meadow vole population resulted, the two species coexisting until April 1974, when most meadow voles disappeared from the grid during a relatively short period. Interspecific aggression levels, as determined from voles temporarily removed from the populations and tested in paired encounters in a laboratory arena, were low during the winter, but increased when males of both species entered reproductive condition in the spring. Microtus was generally dominant in early breeding period encounters, but this dominance declined concurrently with the meadow voles' disappearance from the forest. It is argued that meadow voles did not leave the forest to breed, or because the snow cover melted, since this species will live and reproduce in forest in the absence of Clethrionomys. The results are interpreted as support for an earlier hypothesis that competitive habitat exclusion varies seasonally with reproduction-related aggression. Thus, these species apparently may coexist in either of their preferred habitats when interspecific aggression is low (the nonbreeding season), but this relationship terminates when interspecific aggression levels increase with the resumption of breeding in the spring.

Effect of Orthene® on an unconfined population of the meadow vole (Microtus pennsylvanicus)

1986 ◽  
Vol 64 (1) ◽  
pp. 243-250 ◽  
Author(s):  
David A. Jett ◽  
James D. Nichols ◽  
James E. Hines
Keyword(s):  
Survival Rate ◽  
Population Size ◽  
Weight Change ◽  
Relative Weight ◽  
Reproductive Activity ◽  
Microtus Pennsylvanicus ◽  
Field Application ◽  
Meadow Vole ◽  
Old Field ◽  
Insecticide Treatment

The possible impact on Microtus pennsylvanicus of ground applications of Orthene® insecticide was investigated in old-field habitats in northern Maryland during 1982 and 1983. The treatment grids in 1982 and 1983 were sprayed at 0.62 and 0.82 kg active ingredient/ha, respectively. A capture–recapture design robust to unequal capture probabilities was utilized to estimate population size, survival, and recruitment. Data on reproductive activity and relative weight change were also collected to investigate the effect of the insecticide treatment. There were no significant differences in population size or recruitment between control and treatment grids which could be directly related to the treatment. Survival rate was significantly lower on the treatment grid than on the control grid after spraying in 1983; however, survival rate was higher on the treatment grid after spraying in 1982. Significantly fewer pregnant adults were found on the treatment grid after spraying in 1982, whereas the proportions of voles lactating or with perforate vaginas or open pubic symphyses were slightly higher or remained unchanged during this period. Relative weight change was not affected by the treatment. Results do not indicate any pattern of inhibitory effects from the insecticide treatment. Field application of Orthene® did not have an adverse effect on this Microtus population.

Iodine-131 in Thyroids of the Meadow Vole (Microtus pennsylvanicus) in the Vicinity of the Three Mile Island Nuclear Generating Plant

1981 ◽  
Vol 41 (2) ◽  
pp. 297-301 ◽  
Author(s):  
William R. Field ◽  
Elizabeth H. Field ◽  
David A. Zegers ◽  
Guy L. Steucek
Keyword(s):  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Iodine 131

scholarly journals PREGNANCY-BLOCK IN THE MEADOW VOLE, MICROTUS PENNSYLVANICUS

Reproduction ◽  
1971 ◽  
Vol 24 (2) ◽  
pp. 275-277 ◽  
Author(s):  
F. V. CLULOW ◽  
P. E. LANGFORD
Keyword(s):  
Microtus Pennsylvanicus ◽  
Meadow Vole

scholarly journals Pre-therapeutic Microglia Activation and Sex Determine Therapy Effects of Chronic Immunomodulation

2021 ◽  
Author(s):  
Gloria Biechele ◽  
Tanja Blume ◽  
Maximilian Deussing ◽  
Benedikt Zott ◽  
Yuan Shi ◽  
...  
Keyword(s):  
Spatial Learning ◽  
Microglial Activation ◽  
Translocator Protein ◽  
Learning Performance ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Activated Microglia ◽  
Ppar Γ ◽  
Amyloid Accumulation ◽  
Β Amyloid

Modulation of the innate immune system is emerging as a promising therapeutic strategy against Alzheimer's disease (AD). However, determinants of a beneficial therapeutic effect are ill-understood. Thus, we investigated the potential of 18 kDa translocator protein positron-emission-tomography (TSPO-PET) for assessment of microglial activation in mouse brain before and during chronic immunomodulation. Serial TSPO-PET was performed during five months of chronic microglia modulation by stimulation of peroxisome proliferator-activated receptor (PPAR)-γ with pioglitazone in two different mouse models of AD (PS2APP, AppNL-G-F). Using mixed statistical models on longitudinal TSPO-PET data, we tested for effects of therapy and sex on treatment response. We tested correlations of baseline with longitudinal measures of TSPO-PET, and correlations between PET results with spatial learning performance and β-amyloid accumulation of individual mice. Immunohistochemistry was used to determine the molecular source of the TSPO-PET signal. Pioglitazone-treated female PS2APP and AppNL-G-F mice showed attenuation of the longitudinal increases in TSPO-PET signal when compared to vehicle controls, whereas treated male AppNL-G-F mice showed the opposite effect. Baseline TSPO-PET strongly predicted changes in microglial activation in treated mice (R=-0.874, p<0.0001) but not in vehicle controls (R=-0.356, p=0.081). Reduced TSPO-PET signal upon treatment was associated with better spatial learning and higher fibrillar β-amyloid accumulation. Immunohistochemistry confirmed activated microglia to be the source of the TSPO-PET signal (R=0.952, p<0.0001). TSPO-PET represents a sensitive biomarker for monitoring of immunomodulation and closely reflects activated microglia. Pre-therapeutic assessment of baseline microglial activation and sex are strong predictors of individual immunomodulation effects and could serve for responder stratification.

Paleoecological implications of Late Pleistocene and Holocene microtine rodents from the Bluefish Caves, northern Yukon Territory

1989 ◽  
Vol 26 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Richard E. Morlan
Keyword(s):  
Late Pleistocene ◽  
Growing Season ◽  
Microtus Pennsylvanicus ◽  
Yukon Territory ◽  
Meadow Vole ◽  
Tooth Size ◽  
Microtine Rodents ◽  
Clethrionomys Rutilus ◽  
Tundra Vole ◽  
Dicrostonyx Torquatus

Bluefish Caves 1, 2, and 3 have produced tens of thousands of vertebrate remains among which at least nine species of microtine rodents are represented: red-backed vole, Clethrionomys rutilus; collared lemming, Dicrostonyx torquatus; brown lemming, Lemmus sibiricus; singing vole, Microtus miurus; tundra vole, Microtus oeconomus; meadow vole, Microtus pennsylvanicus; yellow-cheeked or taiga vole, Microtus xanthognathus; muskrat, Ondatra zibethicus; and northern bog lemming, Synaptomys borealis. Late Pleistocene and Holocene components are clearly distinguishable from one another in each of the three caves, and each component can be subdivided within cave 1. This paper discusses (i) variations in taxonomic abundance through time and between site areas, (ii) contrasts in microhabitat between north-facing cave 1 and south-facing cave 2, and (iii) decreases in tooth size that may reflect a reduction in the length of the growing season. A general decrease in diversity is shown to involve increased dominance and decreased species richness and evenness. These changes are attributed to postglacial zonation of habitat.

Sign in / Sign up

Export Citation Format

Share Document