Search PubMed⌕ Search

Biomedical subjects

R J Rodgers

Publications and source records attributed to R J Rodgers.

At least 37 records · Page 2Linked to original sources
PubMed2002

Absence of anxiolytic response to chlordiazepoxide in two common background strains exposed to the elevated plus-maze: importance and implications of behavioural baseline.

Although genetic background is acknowledged as a potentially important determinant of mutant phenotypes, publications on genetically modified mice far outnumber those on progenitor strains. We have recently reported major differences in basal anxiety levels (elevated plus-maze & light/dark exploration) among three strains (C57BL/6JOlaHsd, 129/SvEv and 129S2/SvHsd) employed as progenitor stock in European laboratories (Rodgers et al. in press). Furthermore, the phenotypes of these inbred strains differed significantly from that of an outbred strain (Swiss-Webster) commonly used in behavioural pharmacology. In view of these findings, the present study assessed possible differences in the anxiolytic efficacy of chlordiazepoxide (0, 7.5 & 15.0 mg/kg, IP) in three of these strains (Swiss-Webster (SW), C57BL/6JOIaHsd (C57) & 129S2/SvHsd (129)). Experimentally naive mice were exposed to the elevated plus-maze, sessions were videotaped and behaviour analysed using ethological software. The performance of control subjects confirmed significant strain differences in basal levels of activity (SW > C57 > 129) and anxiety-related behaviours (129 = SW > C57), with hypolocomotion dominating the 129 profile. SW mice displayed an anxioselective response to both doses of chlordiazepoxide (CDP), with significant reductions in open arm avoidance and risk assessment observed in the absence of any change in general activity. In direct contrast, the lower dose of CDP (7.5 mg/kg) was without effect in either inbred strain, whereas treatment with 15.0 mg/kg induced a profile indicative of muscle relaxation/mild sedation in C57 mice and virtually abolished all behavioural activity in 129 mice. Although the absence of an anxiolytic response to CDP in C57 mice may be attributed to their low basal anxiety levels, the profile of 129 mice strongly suggests an abnormality in benzodiazepine/GABAA receptor function. The implications of these findings for research on mutant mice are discussed.

Animals↗
PubMed2002

The effect of obesity on the ratio of type 3 17beta-hydroxysteroid dehydrogenase mRNA to cytochrome P450 aromatase mRNA in subcutaneous abdominal and intra-abdominal adipose tissue of women.

OBJECTIVES: To investigate (1) whether type 3 17beta-hydroxysteroid dehydrogenase (17beta-HSD), the enzyme which catalyzes the conversion of androstenedione to testosterone in the testis, is co-expressed with P450aromatase in the preadipocytes of women, and (2) whether the relative expression of type 3 17beta-HSD and aromatase varies in subcutaneous abdominal vs intra-abdominal adipose tissue of women. SUBJECTS: Subcutaneous abdominal and intra-abdominal adipose tissue was obtained from women undergoing elective abdominal surgery (age 22-78 y, body mass index (BMI) 22.4-52.9 kg/m(2)). MEASUREMENTS: Expression of type 3 17beta-HSD in adipose cell fractions was determined using RT-PCR. Preadipocyte steroidogenesis was investigated in primary cultures using androstenedione as substrate. Messenger RNA levels for type 3 17beta-HSD and aromatase were measured in adipose tissue from the subcutaneous abdominal and intra-abdominal depots using a quantitative multiplex competitive RT-PCR assay. RESULTS: Type 3 17beta-HSD is co-expressed with aromatase in the abdominal preadipocytes of women. Cultured preadipocytes from both subcutaneous abdominal (n=5) and intra-abdominal (n=5) sites converted androstenedione to testosterone, and there was minimal conversion of androstenedione to estrone. Consistent with this, the levels of type 3 17beta-HSD mRNA were significantly higher than aromatase mRNA at both sites (P<0.05; n=8 subcutaneous abdominal, n=12 intra-abdominal adipose tissue). The ratio of levels of 17beta-HSD mRNA to aromatase mRNA in intra-abdominal adipose tissue was positively correlated with BMI (n=11, r=0.61, P<0.05) and waist circumference (n=10, r=0.65, P<0.05). The converse was found in subcutaneous abdominal adipose tissue. CONCLUSION: The intra-abdominal adipose tissue of women may be substantially androgenic, increasingly so with increasing obesity, particularly central obesity. While androgen production by this adipose tissue deposit may not contribute to circulating testosterone levels due to hepatic clearance, it may have hitherto unrecognised local effects in the intra-abdominal adipose tissue and also on the liver via the hepatic portal system. These studies suggest a mechanism linking central obesity with insulin resistance and dyslipidaemia.

17-Hydroxysteroid Dehydrogenases↗
PubMed2002

Composition and morphology of the follicular basal lamina during atresia of bovine antral follicles.

The fate of the follicular basal lamina during atresia was investigated using bovine follicles, in which different follicle phenotypes have been observed. These phenotypes include: healthy follicles with rounded basal granulosa cells with an aligned basal lamina or follicles with columnar basal granulosa cells with a basal lamina of many loops (loopy), and atretic follicles in which either the antral granulosa cells (antral atresia) or the basal cells (basal atresia) die first. Loopy lamina and basal atresia occur only in small antral follicles < 5 mm in diameter. Follicles were collected from cattle of unknown reproductive history and processed for immunohistochemistry and electron microscopy, and from animals in which follicle growth had been monitored by daily measurements of follicle diameter by ultrasonography. Electron microscopic observations of dominant follicles during the growth phase, plateau and regression showed that the basal lamina was still visible and intact upon atresia. These follicles had a conventional aligned basal lamina, which they retained, except for some degree of folding, as they progressed into antral atresia. In small follicles (2-5 mm in diameter), the basal cell shape (rounded or columnar) and appearance of the basal lamina (aligned or of many loops) did not appear to be related to the type of atresia. On atresia the follicular basal laminae retained immunoreactive laminin alpha1 and beta2, type IV collagen alpha1 and nidogen. Laminin alpha2, which may come from the theca, was present in the follicular basal lamina of only 22% of healthy follicles, but was expressed very commonly in 71% of the atretic follicles. Laminin alpha2 expression was found in both phenotypes of healthy follicles, antral and basal atretic follicles, and follicles with aligned or loopy basal laminae. It is concluded that the basal lamina is not degraded upon atresia, but does undergo a variety of other changes.

Animals↗
PubMed2001

Prior test experience compromises the anxiolytic efficacy of chlordiazepoxide in the mouse light/dark exploration test.

It is now well established that prior test experience can alter behavioural baselines and attenuate/abolish the anxiolytic efficacy of benzodiazepines in the elevated plus-maze paradigm. In view of evidence that different models of anxiety measure qualitatively distinct forms of anxiety-like behaviour, it is important to establish whether the effects of prior experience extend to other widely-used tests. The present study assessed the behavioural and pharmacological sequelae of a single undrugged prior exposure to the light/dark exploration (L/D) test in mice, using ethological scoring methods. One group of adult male Swiss-Webster mice was given a single undrugged exposure to the L/D test 24 h prior to drug testing, while another group was completely naïve to the apparatus. On test day, half the animals in each experiential condition were treated with saline and half with an anxiolytic dose (10 mg/kg) of chlordiazepoxide (CDP). When administered to test-naïve animals, CDP induced a clear reduction in anxiety-like behaviour as evidenced by significant increases in exploration of the light compartment (line crossings, % line crossings, and % time) as well as reductions in stretched attend postures (SAPs) and the proportion of SAPs displayed toward the light compartment. The behavioural specificity of these effects was confirmed by the absence of a drug effect on line crossings in the dark compartment, total rearing and grooming. In complete contrast, with the sole exception of a decrease in total SAPs, CDP was without significant behavioural effect in test-experienced mice. As prior test experience did not significantly alter behavioural baselines in the L/D test, a second experiment was designed to investigate the possibility that handling/intraperitoneal injection may have precluded detection of experientially-induced changes in baseline behaviour. Results showed that handling/injection had no effect upon L/D behavioural profiles in either test-naïve or test-experienced subjects, and confirmed that prior experience itself did not modify the primary indices of anxiety in this test. Present data indicate that prior test experience seriously compromises the anxiolytic efficacy of CDP (10 mg/kg) in the mouse L/D test and, together with recent findings in the four-plate test, appear to confirm that an experientially-induced reduction in sensitivity to the anxiolytic effects of benzodiazepines is by no means unique to the elevated plus-maze.

Animals↗
PubMed2001

Dynamics of the membrana granulosa during expansion of the ovarian follicular antrum.

As an endocrine organ, the ovary has some unique characteristics. The formation, the maturation and the regression of the hormone producing cells really determine the timing, the amount and the type of hormone secreted. Here, we focus on the granulosa cells of ovarian follicles which express 17beta-hydroxysteroid dehydrogenase type 1 and cytochrome P450 aromatase. Follicles only produce estradiol late in follicular development before either ovulation or atresia ensues. We discuss the evidence that the membrana granulosa has many characteristics in common with other epithelia, including that it arises from stem cells. The corollary of this is that individual cells within the membrana granulosa are of different ages or stages of specialization. This is evident as regional differences across the membrana granulosa in terms of cell ages, shapes, gene expression, and even behaviour on cell death. We discuss theoretical considerations of the effects of antrum formation on the behavior of the membrana granulosa, and show evidence for differences between follicles in cell shapes, basal lamina phenotypes and location of younger cells, which we speculate is due to different rates of antrum expansion. Clearly, the membrana granulosa is dynamic, and this could explain much about the differences in the behaviors of cells from within the membrana granulosa, and between ovarian follicles.

17-Hydroxysteroid Dehydrogenases↗
PubMed2001

Anxiolytic effects of valproate and diazepam in mice are differentially sensitive to picrotoxin antagonism.

Although it is widely believed that the anxiolytic effects of benzodiazepines are mediated through facilitation of GABA(A) receptor function, behavioural studies have to date provided rather weak support for this hypothesis. In particular, considerable inconsistency has been noted both for the effects of GABAergic manipulations in animal models of anxiety and the ability of GABA(A) receptor antagonists to block the anxiolytic effects of diazepam (DZ) and chlordiazepoxide. In view of the sensitivity of the murine plus-maze to the anxiety-modulating effects of GABAergic agents as well as classical benzodiazepines, the current study examined the extent to which the anxiolytic actions of valproic acid (VPA) and DZ in this test involve picrotoxin (PX)-sensitive receptor mechanisms. Subjects were male DBA/2 mice, test duration was 5 min, and ethological scoring methods were employed. Our results show that, while devoid of intrinsic behavioural effects under present test conditions, PX (0.25-0.5 mg/kg) selectively antagonised the anxiolytic-like (but not other) effects of VPA (400 mg/kg). In contrast, the same doses of PX failed to block any of the behavioural changes induced by DZ (1.5 mg/kg), including disinhibition of open arm exploration. These data suggest that the plus-maze anxiolytic effects of DZ in DBA/2 mice are not mediated through PX-sensitive GABA(A) receptors. Further studies will be required to assess the generality of present findings to other mouse strains, species and behavioural paradigms.

Animals↗
PubMed2001

SB-334867, a selective orexin-1 receptor antagonist, enhances behavioural satiety and blocks the hyperphagic effect of orexin-A in rats.

Intracerebroventricular (i.c.v.) administration of the novel hypothalamic neuropeptide orexin-A stimulates food intake in rats, and delays the onset of behavioural satiety (i.e. the natural transition from feeding to resting). Furthermore, preliminary findings with the selective orexin-1 receptor antagonist, SB-334867, suggest that orexin-A regulation of food intake is mediated via the orexin-1 receptor. At present, however, little is known about either the intrinsic effects of SB-334867 on the normal structure of feeding behaviour, or its effects upon orexin-A-induced behavioural change. In the present study, we have employed a continuous monitoring technique to characterize the effects of SB-334867 (3-30 mg/kg, i.p.) on the microstructure of rat behaviour during a 1-h test with palatable wet mash. Administered alone, SB-334867 (30 mg/kg, but not lower doses) significantly reduced food intake and most active behaviours (eating, grooming, sniffing, locomotion and rearing), while increasing resting. Although suggestive of a behaviourally nonselective (i.e. sedative) action, the structure of feeding behaviour was well-preserved at this dose level, with the reduction in behavioural output clearly attributable to an earlier onset of behavioural satiety. As previously reported, orexin-A (10 microg per rat i.c.v.) stimulated food intake, increased grooming and delayed the onset of behavioural satiety. Pretreatment with SB-334867 dose-dependently blocked these effects of orexin-A, with significant antagonism evident at dose levels (3-10 mg/kg) below those required to produce intrinsic behavioural effects under present test conditions. Together, these findings strongly support the view that orexin-A is involved in the regulation of feeding patterns and that this influence is mediated through the orexin-1 receptor.

Animals↗
PubMed2001

Atresia revisited: two basic patterns of atresia of bovine antral follicles.

Our observations of bovine follicles indicated that the original histological classifications of atresia were inaccurate. A detailed histological, ultrastructural and immunohistochemical study of antral follicles from bovine ovaries collected from an abattoir and from animals whose large follicles had been monitored by ultrasonography was conducted to investigate this further. Nidogen and CD68 were immunolocalized to observe the follicular basal lamina and macrophages, respectively. In randomly collected ovaries, approximately one quarter of all antral follicles were undergoing antral atresia, as designated in this study. Antral atresia was characterized by early destruction of the layers of the membrana granulosa closest to the antrum, whereas the most basal cells remained intact. Numerous pyknotic nuclei were observed in the most antral layers and in the antrum close to the membrana granulosa. This is the classic description of atretic follicles and was observed at all sizes of follicle development and almost universally in large follicles (> 5 mm in diameter), including dominant follicles. Basal atretic follicles, as designated in this study, were almost as prevalent as the antral atretic follicles, and were characterized by initial destruction of the most basal layer of granulosa cells, whereas the cells in the most antral layers remained associated with each other and were predominantly healthy. Pyknotic nuclei and the nuclei of dying basal cells budded into apoptotic bodies were observed rarely. The basal lamina of basal atretic follicles was often breached by macrophages, which were phagocytosing dying basal granulosa cells. The theca was characterized by an increased deposition of collagen, and the cells were orientated randomly, rather than lying parallel to the membrana granulosa as in healthy follicles. Basal atresia occurred in small (< 5 mm in diameter) follicles only. Importantly, these basal atretic follicles were originally identified incorrectly in the literature. Thus, on the basis of the results of this study and another on the expression of steroidogenic enzymes in atretic follicles, it is suggested that the standard biochemical methods for measuring steroid hormone concentrations in follicular fluids to assess atresia should be re-evaluated.

Animals↗
PubMed2000

Dose-response effects of orexin-A on food intake and the behavioural satiety sequence in rats.

Although intracerebroventricular (i.c.v.) administration of orexin-A has been reported to stimulate food intake and/or feeding behaviour in rats, mice and goldfish, little attention has thus far been paid to its effects on normal patterns of feeding. In the present study, a continuous monitoring technique was used to characterise the effects of this novel neuropeptide on the microstructure of rat behaviour during a 1-h test with palatable wet mash. Particular attention was devoted to the behavioural satiety sequence, in which feeding is followed by grooming and resting. Although results confirmed the hyperphagic effects of orexin-A (3.33-30.0 microg i.c. v.), gross behavioural analysis failed to reveal any reliable effects of peptide treatment on eating, drinking, sniffing, grooming, resting, locomotion or rearing. However, microstructural analysis revealed behavioural effects of orexin-A that are both dose- and time-dependent. At lower doses (3.33-10.0 microg), orexin-A primarily delayed behavioural satiety, i.e. the normal transition from eating to resting. In contrast, the 30 microg dose initially induced a sedative-like effect, significantly suppressing eating and other active behaviours for the first 15-20 min of the test period. This sedative-like effect resulted in a phase-shifting of the entire behavioural sequence with higher than control levels of eating, grooming, locomotion, rearing and sniffing observed over the second half of the test session. Present findings illustrate the advantages of microstructural behavioural analysis and suggest that the hyperphagic response to low doses of orexin-A results largely from a delay in behavioural satiety while that seen in response to high doses may occur in rebound to initial behavioural suppression. Further studies will be required to confirm the identity of the specific orexin receptors (i.e. OX(1) or OX(2)) involved in mediating the dose-dependent behavioural effects reported.

Animals↗
PubMed2000

The effects of compounds varying in selectivity as 5-HT(1A) receptor antagonists in three rat models of anxiety.

Compounds varying in selectivity as 5-HT(1A) receptor antagonists have recently been reported to produce benzodiazepine-like antianxiety effects in mice. To assess the cross-species generality of these findings, the present experiments compared the effects of diazepam (0.625-5 mg/kg) with those of several non-selective (MM-77, 0.03-1 mg/kg and pindobind-5-HT(1A), 0.1-5 mg/kg) and selective (WAY100635, 0.01-10 mg/kg, p-MPPI, 0.01-3 mg/kg and SL88.0338, 0.3-10 mg/kg) 5-HT(1A) receptor antagonists in three well-validated anxiolytic screening tests in rats: punished lever-pressing, punished drinking, and the elevated plus-maze. In the punished lever-pressing conflict test, none of the 5-HT(1A) receptor antagonists modified rates of punished responding, whereas in the punished drinking test, WAY100635 (0.3-1 mg/kg), SL88.0338 (3-10 mg/kg), p-MPPI (1 mg/kg), MM-77 (0.03-0.3 mg/kg), but not pindobind-5-HT(1A), produced clear anticonflict activity. However, the increase in punished responding with the 5-HT(1A) compounds was smaller than that produced by diazepam, indicating weaker anxiolytic-like activity. In the elevated plus-maze test, WAY100635 (0.1-0.3 mg/kg), SL88.0338 (0.3-10 mg/kg), MM-77 (0.01-3 mg/kg), pindobind-5-HT(1A) (0.1-3 mg/kg), but not p-MPPI, showed anxiolytic-like activity on traditional behavioral indices, increasing the percentage of time spent in open arms and the percentage of open arm entries. As was the case in the punished drinking test, the magnitude of the positive effects of the 5-HT(1A) compounds was generally smaller than that of diazepam. Of the ethological measures recorded in the plus-maze, all compounds markedly decreased risk assessment (i.e. attempts) over the entire dose-range, but only diazepam clearly increased directed exploration (i.e. head-dipping). Although the present results demonstrate that 5-HT(1A) receptor antagonists elicit anxiolytic-like effects in rats, this action appears to be test-specific and, unlike previous findings in mice, smaller than that observed with benzodiazepines. The data are discussed in relation to the possible relevance of species differences in 5-HT(1A) receptor function and the nature of the anxiety response studied.

Aminopyridines↗
PubMed2000

Extracellular matrix in ovarian follicles.

A lot is known about the control of the development of ovarian follicles by growth factors and hormones, but less is known about the roles of extracellular matrix in the control of follicular growth and development. In this review we focus on the specialized extracellular matrix of the basal laminas that are present in ovarian follicles. These include the follicular basal lamina itself, the Call-Exner bodies of the membrana granulosa, the subendothelial and arteriole smooth muscle basal laminas in the theca, and the basal lamina-like material of the thecal matrix. We discuss the evidence that during follicle development the follicular basal lamina changes in composition, that many of its components are produced by the granulosa cells, and that the follicular basal laminas of different follicles have different ultrastructural appearances, linked to the shape of the aligning granulosa cells. All these studies suggest that the follicular basal lamina is extremely dynamic during follicular development.

Animals↗
PubMed2000

Behavioral profile of wild mice in the elevated plus-maze test for anxiety.

Systematic observations of the defensive behavior of wild rodents have greatly informed the experimental study of anxiety and its neural substrates in laboratory animals. However, as the former work has been almost exclusively carried out in rats, few data are available concerning the reactivity of wild mice to standardized tests of anxiety-related behavior. In the present experiments, we employed ethological measures to examine the behavioral responses of a wild-derived population of house mice (Mus musculus) in the elevated plus-maze. In direct comparisons with laboratory Swiss mice, male wild mice exhibited substantially elevated levels of exploratory activities and an overall "preference" for the open arms of the plus-maze. On re-exposure to the plus-maze, male wild mice showed further increases in open arm exploration, while Swiss mice showed a marked shift to the enclosed parts of the plus-maze. Tested over a single session, female wild mice also exhibited a profile of high open arm exploration, but showed levels of exploratory behaviors and locomotor activity similar to female Swiss counterparts. While exploratory patterns in wild mice show similarities to profiles seen in certain laboratory strains (e.g., BALB/c), wild mice displayed a number of additional behaviors that are unprecedented in plus-maze studies with laboratory mice. These included actual and attempted jumps from the maze, spontaneous freezing, and exploration of the upper ledges of the closed arms. Thus, while in conventional terms the behavior of wild mice was consistent with one of low anxiety-like behavior, the presence of these unique elements instead indicates a profile more accurately characterized by high reactivity and escape motivation. We discuss how the use of an ethological approach to measuring plus-maze behavior can support accurate interpretation of other exceptional profiles in this test, such as those possibly arising from phenotyping of transgenic and gene knockout mice.

Animals↗
PubMed2000

Identification and immunolocalization of decorin, versican, perlecan, nidogen, and chondroitin sulfate proteoglycans in bovine small-antral ovarian follicles.

Proteoglycans (PGs) consist of a core protein and attached glycosaminoglycans (GAGs) and have diverse roles in cell and tissue biology. In follicles PGs have been detected only in follicular fluid and in cultured granulosa cells, and the composition of their GAGs has been determined. To identify PGs in whole ovarian follicles, not just in follicular fluid and granulosa cells, small (1-3-mm) bovine follicles were harvested. A proportion of these was incubated with (35)SO(4) for 24 h to incorporate radiolabel into the GAGs. The freshly harvested and cultured follicles were sequentially extracted with 6 M urea buffer, the same buffer with 0.1% Triton X-100 and then with 0.1 M NaOH. Proteoglycans were subjected to ion-exchange and size-exclusion chromatography. The GAGs were analyzed by chemical and enzymic digestion, and on the basis of their composition, we chose a list of known PGs to measure by ELISA analyses. Versican, perlecan, decorin, but not aggrecan or biglycan, were identified. These, excluding decorin for technical reasons, as well as a basal lamina glycoprotein, nidogen/entactin, were immunolocalized. Versican was localized to the thecal layers, including externa and the interna particularly in an area adjacent to the follicular basal lamina. Perlecan and nidogen were localized to the follicular basal lamina of antral follicles, both healthy and atretic, but not to that of preantral follicles. Both were localized to subendothelial basal laminas, but the former was not readily detected in arteriole smooth muscle layers. This study has confirmed the presence of versican and perlecan, but not the latter as a component of follicular fluid, and identified decorin and nidogen in ovarian antral follicles.

Animals↗
PubMed2000

Ultrastructure of the basal lamina of bovine ovarian follicles and its relationship to the membrana granulosa.

Different morphological phenotypes of follicular basal lamina and of membrana granulosa have been observed. Ten preantral follicles (< 0. 1 mm), and 17 healthy and six atretic antral follicles (0.5-12 mm in diameter) were processed for light and electron microscopy to investigate the relationship the between follicular basal lamina and membrana granulosa. Within each antral follicle, the shape of the basal cells of the membrana granulosa was uniform, and either rounded or columnar. There were equal proportions of follicles </= 4 mm in diameter with columnar basal cells and with rounded basal cells. Larger follicles had only rounded basal cells. Conventional basal laminae of a single layer adjacent to the basal granulosa cells were observed in healthy follicles at the preantral and antral stages. However, at the preantral stage, the conventional types of basal lamina were enlarged or even partially laminated. A second type of basal lamina, described as 'loopy', occurred in about half the preantral follicles and in half the antral follicles </= 4 mm diameter. 'Loopy' basal laminae were not observed in larger follicles. 'Loopy' basal laminae were composed of basal laminae aligning the basal surface of basal granulosa cells, but with additional layers or loops often branching from the innermost layer. Each loop was usually < 1 microm long and had vesicles (20-30 nm) attached to the inner aspect. Basal cellular processes were also common, and vesicles could be seen budding off from these processes. In antral follicles, conventional basal laminae occurred in follicles with rounded basal granulosa cells. Other follicles with columnar cells, and atretic follicles, had the 'loopy' basal lamina phenotype. Thus, follicles have different basal laminae that relate to the morphology of the membrana granulosa.

Animals↗
PubMed1999

Development of the ovarian follicular epithelium.

A lot is known about the endocrine control of the development of ovarian follicles, but a key question now facing researchers is which molecular and cellular processes take part in control of follicular growth and development. The growth and development of ovarian follicles occurs postnatally and throughout adult life. In this review, we focus on the follicular epithelium (membrana granulosa) and its basal lamina. We discuss a model of how granulosa cells arise from a population of stem cells and then enter different lineages before differentiation. The structure of the epithelium at the antral stage of development is presented, and the effects that follicle growth has on the behavior of the granulosa cells are discussed. Finally, we discuss the evidence that during follicle development the follicular basal lamina changes in composition. This would be expected if the behavior of the granulosa cells changes, or if the permeability of the basal lamina changes. It will be evident that the follicular epithelium has similarities to other epithelia in the body, but that it is more dynamic, as gross changes occur during the course of follicle development. This basic information will be important for the development of future reproductive technologies in both humans and animals, and possibly for understanding polycystic ovarian syndrome in women.

Animals↗
PubMed1999

Characterization of the translated products of the alternatively spliced luteinizing hormone receptor in the ovine ovary throughout the oestrous cycle.

The luteinizing hormone receptor (LHR) is alternatively spliced. It is not known if the alternatively spliced mRNAs are translated in vivo, or indeed if they have any vital role to play. The B splice form has been detected in every species examined, and it encodes a putative protein with a high affinity LH/CG binding domain but no trans-membrane or intra-cellular domains. We raised antisera that recognize the putative protein of the B form, and the closely related G form, and showed that the B form mRNA is translated in the ovine ovary, but not kidney or liver. It localized to the luteal cytosolic and microsomal fractions and the levels declined during regression induced by treatment with prostaglandin F2alpha. We examined alternative splicing by RNase protection analyses and RT-PCR analyses of healthy pre-ovulatory follicles, atretic or steroidogenically-inactive follicles, and of newly formed, mid-luteal and regressing corpora lutea. There was approximately 5-fold more B form mRNA than A form. Thus we have evidence that the LHR B form is translated in vivo, but no evidence that alternative splicing of the LHR mRNA is differentially regulated, throughout the oestrous cycle.

Alternative Splicing↗
PubMed1999

Behavioural profiles in the mouse defence test battery suggest anxiolytic potential of 5-HT(1A) receptor antagonists.

RATIONALE: Compounds varying in selectivity as 5-HT1A receptor antagonists have recently been reported to produce anxiolytic-like effects comparable to those of benzodiazepines in the mouse elevated plus-maze procedure. OBJECTIVE: In view of the potential clinical significance of these findings, the present experiments compared the behavioural effects of diazepam (0.5-3.0 mg/kg) with those of several non-selective 5-HT1A receptor antagonists [NAN-190, 0.1-3.0 mg/kg, MM-77, 0.03-1.0 mg/kg, (S)-UH-301, 0.3-3.0 mg/kg and pindobind-5-HT1A, 0.03-1.0 mg/kg], and three selective 5-HT1A receptor antagonists (WAY100635, 0.01-3.0 mg/kg, p-MPPI, 0.1-3.0 mg/kg and SL88.0338, 0.3-3.0 mg/kg) in the mouse defence test battery (MDTB). METHODS: In this well-validated anxiolytic screening test, Swiss mice are directly confronted with a natural threat (a rat) as well as situations associated with this threat. Primary measures taken during and after rat confrontation were flight, risk assessment (RA), defensive threat/attack and escape attempts. RESULTS: Diazepam significantly decreased flight reactions after the rat was introduced into the runway, reduced RA activities of mice chased by the rat, increased RA responses displayed when subjects were constrained in a straight alley and reduced defensive upright postures and biting upon forced contact. All the selective 5-HT1A receptor antagonists and NAN-190 also reduced flight, RA in the chase test, and defensive threat and attack behaviours. (S)-UH-301 and pindobind-5-HT1A reduced RA in the chase test, but only partially modified defensive threat and attack. Unlike the other drugs tested, MM-77 produced significant effects only at doses which also markedly reduced spontaneous locomotor activity, suggesting a behaviourally non-specific action. In contrast to diazepam, the 5-HT1A receptor ligands failed to affect RA in the straight alley test. Following removal of the rat from the test area, only diazepam and (S)-UH-301 reduced escape behaviour (contextual defence) at doses which did not decrease locomotion. Overall, the present findings indicate that except for one RA behaviour and escape responses, the 5-HT1A receptor ligands studied modified the same defensive behaviours as diazepam, suggesting potential therapeutic efficacy in the management of anxiety disorders. However, the magnitude of the effects of the 5-HT1A compounds on defence was generally smaller than that of the benzodiazepine. CONCLUSION: As all of the 5-HT1A compounds tested in this series share antagonistic activity in models of postsynaptic 5-HT1A receptor function, it is proposed that this action accounts for their effects on defence.

Animals↗