Behavioural response of sexually naïve and experienced male rats to the smell of 6-methyl-5-hepten-2-one and female rat faeces.

Sexually experienced male rats display penile erections when exposed to faeces from mammalian females in oestrus (Rampin et al., Behav Brain Res, 172:169, 2006), suggesting that specific odours indicate female receptiveness across species. However, it is unknown to what extent the sexual response observed results from an odorous conditioning acquired during sexual experience.

Brain processing of biologically relevant odors in the awake rat, as revealed by manganese-enhanced MRI.

Background: So far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging analyses have not yet been performed beyond the olfactory bulb.

Electrophysiological responses of rat olfactory tubercle neurons to biologically relevant odours.

Biologically relevant odours were used to stimulate olfactory tubercle neurons in anaesthetized male rats. Among 120 recorded neurons, 118 showed spontaneous activity (mean firing rate, 15.0 ± 1.

Effects of manganese injected into rat nostrils: implications for in vivo functional study of olfaction using MEMRI.

Manganese-enhanced magnetic resonance imaging (MEMRI) is a powerful tool for visualizing neuronal pathways and mapping brain activity modulation. A potential drawback of MEMRI lies in the toxic effects of manganese (Mn), which also depend on its administration route. The aim of this study was to analyze the effects of Mn doses injected into the nostrils of rats on both olfactory perception and MRI contrast enhancement.

Iterative algorithm for spatial and intensity normalization of MEMRI images. Application to tract-tracing of rat olfactory pathways.

Manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) is an emerging technique for visualizing neuronal pathways and mapping brain activity modulation in animal models. Spatial and intensity normalizations of MEMRI images acquired from different subjects are crucial steps as they can influence the results of groupwise analysis. However, no commonly accepted procedure has yet emerged.

A mixture of odorant molecules potentially indicating oestrus in mammals elicits penile erections in male rats.

A common set of odorous molecules may indicate female receptiveness across species, as male rats display sexual arousal when exposed to the odour of oestrous faeces from rats, vixens and mares. More than 900 different compounds were identified by GC-MS analyses performed on faeces samples from di-oestrous and oestrous females and from males of the three species. Five carboxylic acids were found in lower concentrations in faeces from all oestrous females.

Statistical analysis of 3D images detects regular spatial distributions of centromeres and chromocenters in animal and plant nuclei.

In eukaryotes, the interphase nucleus is organized in morphologically and/or functionally distinct nuclear "compartments". Numerous studies highlight functional relationships between the spatial organization of the nucleus and gene regulation. This raises the question of whether nuclear organization principles exist and, if so, whether they are identical in the animal and plant kingdoms.

Three-dimensional macronutrient-associated Fos expression patterns in the mouse brainstem.

Background: The caudal brainstem plays an important role in short-term satiation and in the control of meal termination. Meal-related stimuli sensed by the gastrointestinal (GI) tract are transmitted to the area postrema (AP) via the bloodstream, or to the nucleus tractus solitarii (NTS) via the vagus nerve. Little is known about the encoding of macronutrient-specific signals in the caudal brainstem.

Modeling the 3D functional architecture of the nucleus in animal and plant kingdoms.

Compartmentalization is one of the fundamental principles which underly nuclear function. Numerous studies describe complex and sometimes conflicting relationships between nuclear gene positioning and transcription regulation. Therefore the question is whether topological landmarks and/or organization principles exist to describe the nuclear architecture and, if existing, whether these principles are identical in the animal and plant kingdoms.

3D fluorescent in situ hybridization using Arabidopsis leaf cryosections and isolated nuclei.

Background: Fluorescent hybridization techniques are widely used to study the functional organization of different compartments within the mammalian nucleus. However, few examples of such studies are known in the plant kingdom. Indeed, preservation of nuclei 3D structure, which is required for nuclear organization studies, is difficult to fulfill.

Three-dimensional statistical modeling of neuronal populations: illustration with spatial localization of supernumerary neurons in the locus coeruleus of quaking mutant mice.

An algorithm for the three-dimensional statistical representation of neuronal populations was designed and implemented. Using this algorithm a series of 3D models, calculated from repeated histological experiments, can be combined to provide a synthetic vision of a population of neurons taking into account biological and experimental variability. Based on the point process theory, our algorithm allows computation of neuronal density maps from which isodensity surfaces can be readily extracted and visualized as surface models revealing the statistical organization of the neuronal population under study.

Are oestrus odours species specific?

Adult male rats were exposed to faeces odours of three animal species (rat, fox and horse). They displayed erections in the presence of faeces from oestrous females (whatever the species). In addition, fox faeces (whatever the gender or hormonal status) elicited an expected freezing reaction.

Possible neural mediation of the central effects of oxytocin on uterine motility.

The central nervous system contains the nuclei at the origin of autonomic and neuroendocrine pathways to the uterus. Although the anatomical basis of these pathways is known, the conditions of their recruitment and their interactions in the context of copulation remain to be explored. We tested the hypothesis that some central mechanisms could simultaneously recruit both pathways to the uterus.

Free-D: an integrated environment for three-dimensional reconstruction from serial sections.

Three-dimensional (3D) reconstruction is a powerful tool to investigate complex neuroanatomical organizations. 3D models are often generated by piling up registered segmentations carried out on serial sections labeled by histological means. However, these models suffer limitations (incompleteness and lack of statistical representativity), which can be overcome by model averaging and fusion.

Spinal effects of oxytocin on uterine motility in anesthetized rats.

The rat uterus receives an innervation from the lumbosacral and thoracolumbar segments of the spinal cord. These segments receive descending oxytocinergic projections from the paraventricular nucleus of the hypothalamus. We tested the hypothesis that oxytocin regulates uterine motility through a spinal site of action.

Spinal control of erection by glutamate in rats.

The lumbosacral spinal network controlling penile erection is activated by information from peripheral and supraspinal origins. We tested the hypothesis that glutamate, released by sensory afferents from the genitals, activates this proerectile network. In anesthetized intact and T8 spinalized (i.

Spatial segregation within the sacral parasympathetic nucleus of neurons innervating the bladder or the penis of the rat as revealed by three-dimensional reconstruction.

The purpose of the present investigations was (1) to examine the spatial organization of preganglionic neurons of the sacral parasympathetic nucleus in the lumbosacral spinal cord of male adult rats and (2) to search, in this nucleus, for a possible segregation of sub-populations of neurons innervating the penis or the bladder, respectively. To estimate their spatial organization, neurons of the sacral parasympathetic nucleus were retrogradely labeled by wheat germ agglutinin coupled to horseradish peroxidase applied to the central end of the sectioned pelvic nerve. The sub-populations of lumbosacral neurons innervating the corpus cavernosum of the penis or the dome of the bladder were identified using transsynaptic retrograde labeling by pseudorabies virus injected into these organs in different rats.

Abnormal postnatal ontogeny of the locus coeruleus in the epileptic mutant mouse quaking.

The tonic-clonic convulsions of the quaking mutant mice have been shown to be associated with the hyperplasia of the nucleus locus coeruleus, the origin of most brain noradrenergic neurons. In the present study, the postnatal ontogeny of the locus coeruleus has been studied by tyrosine hydroxylase immunolabeling in the mutant mice quaking and their controls at postnatal days 1, 30 and 90. In the control mice, the number of immunoreactive neuronal cell bodies increased significantly in the rostral half of the locus coeruleus between birth and postnatal day 30, while it decreased significantly in the caudal half between birth and adulthood.

Spatio-temporal heterogeneity and cell-specificity of long-term potentiation-induced mRNA expression in the dentate gyrus in vivo.

Gene expression in neurones can vary in response to neuronal activation. In this study, to analyse the spatio-temporal dynamics of the transcriptional response of three genes following the induction of long-term potentiation within the entire dentate gyrus in vivo, two new complementary approaches based on in situ hybridisation were developed: three-dimensional reconstruction of the pattern of mRNA expression within the entire dentate gyrus; and radioactive co-detection of two mRNA species allowing quantification of two different mRNAs in the same brain section. Zif268, Homer and syntaxin 1B genes were studied, and their regulated expression was examined three times after the induction of long-term potentiation.

Intrauterine growth retardation does not alter the distribution of tyrosine hydroxylase-immunoreactive neurons of A8, A9 and A10 groups in the rat: a three-dimensional reconstruction study.

The purpose of the present investigation was to evaluate possible effects of severe prenatal hypotrophy on the number and spatial distribution of tyrosine hydroxylase-immunoreactive neurons of the A8, A9 and A10 cell groups in the rat brain. Prenatal hypotrophy was induced in rat pups by ligaturing one uterine artery in pregnant rats on the 17th day of gestation. This procedure induces a severe growth retardation, which is never caught up with, even at adulthood.

Three-dimensional distribution of nigrostriatal neurons in the rat: relation to the topography of striatonigral projections.

Functional regions of the rat striatum related to identified cortical territories were injected ionophoretically with wheat germ agglutinin coupled to horseradish peroxidase. Coronal serial sections were cut throughout the substantia nigra. The distributions of labelled striatal projections and nigrostriatal neurons were studied.

Computer assisted three-dimensional reconstruction of brain regions from serial section digitized images. Application to the organization of striato-nigral relationships in the rat.

We have developed a software which allows the three-dimensional reconstruction of brain regions from serial section digitized images. This software, which generates wire-frame three dimensional models, requires at least a 486 PC microcomputer running Microsoft Windows (3.x or 95).

Distribution of [3H]clonidine binding sites in the brain of the convulsive mutant quaking mouse: a radioautographic analysis.

The radioautographic analysis of [3H]clonidine binding was performed on brain slices from the convulsive mutant mice quaking and their controls of the same strain. In the quaking mice significant increases were observed mostly in the brainstem and the cerebellum, but also in a few regions of the forebrain, such as the lateral and medial thalamic nuclei, the medial geniculate nucleus, the amygdala and the hypothalamus. Other regions, such as the cerebral cortex and the hippocampus, which are classically involved in various models of epilepsy, but not in the quaking mice, did not show any modification of [3H]clonidine binding.

The quaking mouse: an epileptic mutant with alterations affecting the modulatory mechanisms of the NMDA receptor complex.

The binding of [3H]glutamate and of [3H]1-(1-(2-thienyl)cyclohexyl)piperidine [( 3H]TCP) has been examined in the genetically epileptic mutant mouse, quaking. The density of [3H]glutamate binding sites did not differ between the quaking mice and their controls of the same strain. In the absence of exogenous glutamate or glycine, the density of [3H]TCP binding sites was also similar in the two strains.

Anticonvulsant effects of antagonists of the N-methyl-D-aspartate receptor complex in a genetic model of epilepsy: the quaking mouse.

Tonic-clonic convulsions of mutant quaking mice were antagonized by the intracerebroventricular injection of N-methyl-D-aspartate receptor antagonists. The competitive antagonists, CPP (3-((+/-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid) and CGS 19755 (cis-4-(phosphonomethyl)-2-piperidine carboxylic acid), exerted a partial anticonvulsant action, with ED50S of 0.115 and 0.