Pflugers Archiv-european Journal of Physiology, 2001
Effects of the antidepressant drug mirtazapine on plasma levels and on the kinetics of injected h... more Effects of the antidepressant drug mirtazapine on plasma levels and on the kinetics of injected histamine were studied in the cat. In the dose of 0.6 mg/kg mirtazapine did not affect the characteristics of the elimination curve of histamine. The higher dose of mirtazapine (1.2 mg/kg) prevented the increase of plasma histamine levels.
In the interpretation of measured reflectance data it is important to consider those surface radi... more In the interpretation of measured reflectance data it is important to consider those surface radiation effects which make a significant contribution to the overall irradiation pattern. A model was constructed for furrowed bare soil surfaces which includes the direct cross-radiation effect between the surface elements. According to the model computations performed the direct cross-radiation plays a significant role in the measured, reflected signal intensity. The computational method developed is suitable for including the direct cross-radiation effect in surface radiation models in the optical region.
We previously found that both male and female aromatase knockout (ArKO) mice, which cannot synthe... more We previously found that both male and female aromatase knockout (ArKO) mice, which cannot synthesize estrogens due to a targeted mutation of the aromatase gene, showed less investigation of volatile body odors from anesthetized conspecifics of both sexes in Y-maze tests. We now ask whether ArKO mice are in fact capable of discriminating between and/or responding to volatile odors. Using habituation/ dishabituation tests, we found that gonadectomized ArKO and wild-type (WT) mice of both sexes, which were tested without any sex hormone replacement, reliably distinguished between undiluted volatile urinary odors of either adult males or estrous females versus deionized water as well as between these two urinary odors themselves. However, ArKO mice of both sexes were less motivated than WT controls to investigate same-sex odors when they were presented last in the sequence of stimuli. In a second experiment, we compared the ability of ArKO and WT mice to respond to decreasing concentrations of either male or female urinary odors. We found a clear-cut sex difference in urinary odor attraction thresholds among WT mice: WT males failed to respond to urine dilutions higher than 1:20 by volume, whereas WT females continued to respond to urine dilutions up to 1:80. Male ArKO mice resembled WT females in their ability to respond to lower concentrations of urinary odors, raising the possibility that the observed sex difference among WT mice in urine attraction thresholds results from the perinatal actions of estrogen in the male nervous system. Female ArKO mice failed to show significant dishabituation responses to two (1:20 and 1:80) dilutions of female urine, perhaps, again, because of a reduced motivation to investigate less salient, samesex urinary odors. Previously observed deficits in the preference of ArKO male and female mice to approach volatile body odors from conspecifics of either sex cannot be attributed to an inability of ArKO subjects to discriminate these odors according to sex but instead may reflect a deficient motivation to approach same-sex odors, especially when their concentration is low. D
Rationale and objectives The aim of the present study was to investigate the possible role of oes... more Rationale and objectives The aim of the present study was to investigate the possible role of oestrogen in schizophrenia by comparing aromatase knockout (ArKO) mice, which are unable to produce oestrogen, with wild-type controls using two behavioural animal models with relevance to the illness, psychotropic drug-induced locomotor hyperactivity and prepulse inhibition (PPI). Results Baseline PPI was not different between ArKO and controls. Treatment with apomorphine, MK-801 and amphetamine caused disruption of PPI in all groups. However, in female but not male ArKO mice, the effect of both apomorphine and amphetamine was reduced. In female ArKO mice, amphetamine-induced hyperlocomotion was markedly reduced, but in male mice, the genotype difference was far smaller. Female but not male ArKO mice also showed a reduction of phencyclidine-induced locomotor hyperactivity. The density of dopamine transporters, but not D1 and D2 receptors, was significantly increased in the caudate putamen of male but not female ArKO mice compared to wild-type mice. This could represent a compensatory dopaminergic upregulation in male ArKO mice. Conclusion Because of their lack of oestrogen production, it was anticipated that ArKO mice would display enhanced effects of amphetamine on locomotor activity and PPI. Instead, in these animals, aromatase knockout appeared to be ‘protective’. This may represent limitations in the ability to model a complex illness such as schizophrenia in a constitutive knockout model, such as ArKO mice. Moreover, the current results may point at the involvement of other sex steroids, which are also altered in ArKO mice, in dopaminergic control of behaviour.
Models for the forecasting of crop yields using remotely-sensed satellite data are studied intens... more Models for the forecasting of crop yields using remotely-sensed satellite data are studied intensively worldwide. After reviewing the experience gained by other researchers in this field, we selected procedures which might be suitable for the estimation of corn and wheat yields in Hungary. In order to study the relations between various remotely-sensed spectral data (and their combinations) and the actually measured final yields we investigated archived agricultural and Landsat MSS spectral data for 1984. A linear relation has been sought and found between the yield data for 47 corn and 55 wheat fields in Hajdú-Bihar county and various weighted and summed spectral quantities. Among the vegetation indices derived from satellite data and corrected for atmospheric effects the most promising were the spectral indices sensitive to the green biomass. The latter, summed over a certain period in the growing season, exhibited a regression of 45-86 per cent, depending on the crop and the period of summation. Using the best models we performed regional yield estimation studies on 295 winter wheat and 218 corn fields. Taking half the crop fields used in the study we determined the yield estimation model and used this to estimate the overall crop production for the other half of the fields. The error of overall corn production estimated by this way turn out to be less than 2 per cent. The model developed for winter wheat proved to be sensitive to the wheat variety.
In order to examine the effect of estrogen on facial pain, we first compared the face-rubbing evo... more In order to examine the effect of estrogen on facial pain, we first compared the face-rubbing evoked by a formalin injection in the lip of aromatase-knockout (ArKO) mice, lacking endogenous estrogen production, 17b-estradiol-treated ArKO mice (ArKO-E2) and wild-type (WT) littermates. During the 'acute' phase of pain the time spent rubbing was similar in the three groups, whereas during the following 'interphase' and the second phase of pain, grooming was increased in ArKO mice. Estradiol-treatment restored a behaviour similar to WT group. To better understand estrogens modulation on pain processes, we examined changes in 5-HT and CGRP innervations of trigeminal nucleus caudalis (TNC) in ArKO, ArKO-E2 and WT groups sacrified during the interphase. Whereas serotonin and CGRP immunoreactivities were comparable in WT and ArKO non-injected control groups, our data showed that 9 min after formalin injection, the density of serotoninergic terminals increased significantly in WT, but not in ArKO mice, while that of CGRP-immunoreactive fibers was lower in WT than in ArKO mice on the injected side. Estradiol-treatment only partially reversed these changes in ArKO-E2 mice. We conclude that estrogen deprivation in ArKO mice can be responsible for increased nociceptive response and that it is accompanied by transmitter changes favouring pro-over anti-nociceptive mechanisms in TNC during interphase of the formalin model. That estradioltreatment completely reverses the behavioural abnormality suggests that estrogens absence produces chiefly functional activation-dependent changes. However, the fact that the immunohistochemical abnormalities were not totally normalized by estradiol-treatment suggested that some permanent developmental alterations may occur in ArKO mice. q
Pflugers Archiv-european Journal of Physiology, 2001
Effects of the antidepressant drug mirtazapine on plasma levels and on the kinetics of injected h... more Effects of the antidepressant drug mirtazapine on plasma levels and on the kinetics of injected histamine were studied in the cat. In the dose of 0.6 mg/kg mirtazapine did not affect the characteristics of the elimination curve of histamine. The higher dose of mirtazapine (1.2 mg/kg) prevented the increase of plasma histamine levels.
In the interpretation of measured reflectance data it is important to consider those surface radi... more In the interpretation of measured reflectance data it is important to consider those surface radiation effects which make a significant contribution to the overall irradiation pattern. A model was constructed for furrowed bare soil surfaces which includes the direct cross-radiation effect between the surface elements. According to the model computations performed the direct cross-radiation plays a significant role in the measured, reflected signal intensity. The computational method developed is suitable for including the direct cross-radiation effect in surface radiation models in the optical region.
We previously found that both male and female aromatase knockout (ArKO) mice, which cannot synthe... more We previously found that both male and female aromatase knockout (ArKO) mice, which cannot synthesize estrogens due to a targeted mutation of the aromatase gene, showed less investigation of volatile body odors from anesthetized conspecifics of both sexes in Y-maze tests. We now ask whether ArKO mice are in fact capable of discriminating between and/or responding to volatile odors. Using habituation/ dishabituation tests, we found that gonadectomized ArKO and wild-type (WT) mice of both sexes, which were tested without any sex hormone replacement, reliably distinguished between undiluted volatile urinary odors of either adult males or estrous females versus deionized water as well as between these two urinary odors themselves. However, ArKO mice of both sexes were less motivated than WT controls to investigate same-sex odors when they were presented last in the sequence of stimuli. In a second experiment, we compared the ability of ArKO and WT mice to respond to decreasing concentrations of either male or female urinary odors. We found a clear-cut sex difference in urinary odor attraction thresholds among WT mice: WT males failed to respond to urine dilutions higher than 1:20 by volume, whereas WT females continued to respond to urine dilutions up to 1:80. Male ArKO mice resembled WT females in their ability to respond to lower concentrations of urinary odors, raising the possibility that the observed sex difference among WT mice in urine attraction thresholds results from the perinatal actions of estrogen in the male nervous system. Female ArKO mice failed to show significant dishabituation responses to two (1:20 and 1:80) dilutions of female urine, perhaps, again, because of a reduced motivation to investigate less salient, samesex urinary odors. Previously observed deficits in the preference of ArKO male and female mice to approach volatile body odors from conspecifics of either sex cannot be attributed to an inability of ArKO subjects to discriminate these odors according to sex but instead may reflect a deficient motivation to approach same-sex odors, especially when their concentration is low. D
Rationale and objectives The aim of the present study was to investigate the possible role of oes... more Rationale and objectives The aim of the present study was to investigate the possible role of oestrogen in schizophrenia by comparing aromatase knockout (ArKO) mice, which are unable to produce oestrogen, with wild-type controls using two behavioural animal models with relevance to the illness, psychotropic drug-induced locomotor hyperactivity and prepulse inhibition (PPI). Results Baseline PPI was not different between ArKO and controls. Treatment with apomorphine, MK-801 and amphetamine caused disruption of PPI in all groups. However, in female but not male ArKO mice, the effect of both apomorphine and amphetamine was reduced. In female ArKO mice, amphetamine-induced hyperlocomotion was markedly reduced, but in male mice, the genotype difference was far smaller. Female but not male ArKO mice also showed a reduction of phencyclidine-induced locomotor hyperactivity. The density of dopamine transporters, but not D1 and D2 receptors, was significantly increased in the caudate putamen of male but not female ArKO mice compared to wild-type mice. This could represent a compensatory dopaminergic upregulation in male ArKO mice. Conclusion Because of their lack of oestrogen production, it was anticipated that ArKO mice would display enhanced effects of amphetamine on locomotor activity and PPI. Instead, in these animals, aromatase knockout appeared to be ‘protective’. This may represent limitations in the ability to model a complex illness such as schizophrenia in a constitutive knockout model, such as ArKO mice. Moreover, the current results may point at the involvement of other sex steroids, which are also altered in ArKO mice, in dopaminergic control of behaviour.
Models for the forecasting of crop yields using remotely-sensed satellite data are studied intens... more Models for the forecasting of crop yields using remotely-sensed satellite data are studied intensively worldwide. After reviewing the experience gained by other researchers in this field, we selected procedures which might be suitable for the estimation of corn and wheat yields in Hungary. In order to study the relations between various remotely-sensed spectral data (and their combinations) and the actually measured final yields we investigated archived agricultural and Landsat MSS spectral data for 1984. A linear relation has been sought and found between the yield data for 47 corn and 55 wheat fields in Hajdú-Bihar county and various weighted and summed spectral quantities. Among the vegetation indices derived from satellite data and corrected for atmospheric effects the most promising were the spectral indices sensitive to the green biomass. The latter, summed over a certain period in the growing season, exhibited a regression of 45-86 per cent, depending on the crop and the period of summation. Using the best models we performed regional yield estimation studies on 295 winter wheat and 218 corn fields. Taking half the crop fields used in the study we determined the yield estimation model and used this to estimate the overall crop production for the other half of the fields. The error of overall corn production estimated by this way turn out to be less than 2 per cent. The model developed for winter wheat proved to be sensitive to the wheat variety.
In order to examine the effect of estrogen on facial pain, we first compared the face-rubbing evo... more In order to examine the effect of estrogen on facial pain, we first compared the face-rubbing evoked by a formalin injection in the lip of aromatase-knockout (ArKO) mice, lacking endogenous estrogen production, 17b-estradiol-treated ArKO mice (ArKO-E2) and wild-type (WT) littermates. During the 'acute' phase of pain the time spent rubbing was similar in the three groups, whereas during the following 'interphase' and the second phase of pain, grooming was increased in ArKO mice. Estradiol-treatment restored a behaviour similar to WT group. To better understand estrogens modulation on pain processes, we examined changes in 5-HT and CGRP innervations of trigeminal nucleus caudalis (TNC) in ArKO, ArKO-E2 and WT groups sacrified during the interphase. Whereas serotonin and CGRP immunoreactivities were comparable in WT and ArKO non-injected control groups, our data showed that 9 min after formalin injection, the density of serotoninergic terminals increased significantly in WT, but not in ArKO mice, while that of CGRP-immunoreactive fibers was lower in WT than in ArKO mice on the injected side. Estradiol-treatment only partially reversed these changes in ArKO-E2 mice. We conclude that estrogen deprivation in ArKO mice can be responsible for increased nociceptive response and that it is accompanied by transmitter changes favouring pro-over anti-nociceptive mechanisms in TNC during interphase of the formalin model. That estradioltreatment completely reverses the behavioural abnormality suggests that estrogens absence produces chiefly functional activation-dependent changes. However, the fact that the immunohistochemical abnormalities were not totally normalized by estradiol-treatment suggested that some permanent developmental alterations may occur in ArKO mice. q
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