Central autonomic control of the bone marrow: multisynaptic tract tracing by recombinant pseudorabies virus

Bone marrow is the primary place of hematopoiesis, where the development, survival and release of multipotent stem cells, progenitors, precursors and mature cells are under continuous humoral and neural control. Dense network of nerve fibers, containing various neurotransmitters is found in the bone marrow, however, the central neuronal circuit that regulates the activities of the bone marrow through these fibers remained unexplored. Transsynaptically connected neurons were mapped by virus-based transneuronal tracing technique using two isogenic, genetically engineered pseudorabies viruses, Bartha-DupGreen and Ba-DupLac expressing green fluorescent protein and beta-galactosidase, respectively. Bartha-DupGreen was injected into the femoral bone marrow of male rats and the progression of infection was followed 4-7 days post-inoculation. Virus-labeled cells were revealed in ganglia of the paravertebral chain and in the intermediolateral cell column of the lower thoracic spinal cord. Neurons were retrogradely labeled in the C1, A5, A7 catecholaminergic cell groups and several other nuclei of the ventrolateral and ventromedial medulla, the periaqueductal gray matter, the paraventricular and other hypothalamic nuclei, and in the insular and piriform cortex. Nerve transections and double-virus tracing from the bone marrow and the surrounding muscles were used to confirm the specific spreading of the virus. These results provide anatomical evidence for the CNS control of the bone marrow and identify putative brain areas, which are involved in autonomic regulation of the hematopoiesis, the release of progenitor cells, the blood supply and the immune cell function in the bone marrow.

Transneuronal labelling of nerve cells in the CNS of female rat from the mammary gland by viral tracing technique

Using the viral transneuronal tracing technique, the cell groups in the CNS transneuronally connected with the female mammary gland were detected. Lactating and non-lactating female rats were infected with pseudorabies virus injected into the mammary gland. The other group of animals was subjected to virus injection into the skin of the back. Four days after virus injection, infected neurons detected by immunocytochemistry, were present in the dorsal root ganglia ipsilateral to inoculation and in the intermediolateral cell column of the spinal cord. In addition, a few labelled cells could be detected in the dorsal horn and in the central autonomic nucleus (lamina X) of the spinal cord. At this survival time several brain stem nuclei including the A5 noradrenergic cell group, the caudal raphe nuclei (raphe obscurus, raphe pallidus, raphe magnus), the A1/C1 noradrenergic and adrenergic cell group, the nucleus of the solitary tract, the area postrema, the gigantocellular reticular nucleus, and the locus coeruleus contained virus-infected neurons. In some animals, additional cell groups, among others the periaqueductal gray and the red nucleus displayed labelling. In the diencephalon, a significant number of virus-infected neurons could be detected in the hypothalamic paraventricular nucleus. In most cases, virus-labelled neurons were present also in the lateral hypothalamus, in the retrochiasmatic area, and in the anterior hypothalamus. In the telencephalon, in some animals a few virus-infected neurons could be found in the preoptic area, in the bed nucleus of the stria terminalis, in the central amygdala, and in the somatosensory cortex. At the longer (5 days) survival time each cell group mentioned displayed immunopositive neurons, and the number of infected cells increased. The pattern of labelling was similar in animals subjected to virus inoculation into the mammary gland and into the skin. The distribution and density of labelling was similar in lactating and non-lactating rats. The present findings provide the first morphological data on the localization of CNS structures connected with the preganglionic neurons of the sympathetic motor system innervating the mammary gland. It may be assumed that the structures found virus-infected belong to the neuronal circuitry involved in the control of the sympathetic motor innervation of the mammary gland.

Identification of CNS neurons involved in the innervation of the epididymis: a viral transneuronal tracing study

Cell groups of the spinal cord and the brain transsynaptically connected with the epididymis (caput, cauda) were identified by means of the viral transneuronal tracing technique. Pseudorabies virus was injected into the caput or the cauda epididymidis, and after survival times 4 and 5 days, the spinal cord and brain were processed immunocytochemically. Virus-labeled neurons could be detected in the preganglionic sympathetic neurons (lower thoracic and upper lumbar segments) and following virus injection into the cauda epididymidis, also in the sacral parasympathetic nucleus (L6-S1). Virus-infected perikarya were present in several brain stem nuclei (lateral reticular nucleus, gigantocellular and paragigantocellular nucleus, A5 noradrenergic cell group, caudal raphe nuclei, locus coeruleus, Barrington's nucleus, nucleus of the solitary tract, periaqueductal gray) and in the diencephalon (hypothalamic paraventricular nucleus, lateral hypothalamus). At the longer survival time, some telencephalic structures also exhibited virus-labeled neurons. The distribution of infected neurons in the brain was similar after virus injection into the caput or cauda epididymidis; however, earlier onset of infection was observed after inoculation into the cauda. The present findings provide the first morphological data on a multisynaptic circuit of neurons innervating the epididymis and presumably involved in the control of epididymal functions. reserved.

Central nervous system structures labelled from the testis using the transsynaptic viral tracing technique

In the present study, the transneuronal transport of neurotrophic virus technique was used to identify cell groups of the spinal cord and the brain that are transsynaptically connected with the testis. Pseudorabies virus was injected into the testis and after survival times of 3-6 days, the spinal cord and brain were processed immunocytochemically using a polyclonal antibody against the virus. Virus-infected perikarya were detected in the preganglionic neurones of the spinal cord (T10-L1, L5-S1) and in certain cell groups and areas of the brain stem, the hypothalamus and the telencephalon. In the brain stem, the cell groups and areas in which labelled neurones were present included, among others, the nucleus of the solitary tract, the caudal raphe nuclei, the locus coeruleus and the periaqueductal grey of the mesencephalon. In the hypothalamus, virus infected perikarya were observed in the paraventricular nucleus and in certain other cell groups. Telencephalic structures containing labelled neurones included the preoptic area, the bed nucleus of the stria terminalis, the central amygdala and the insular cortex. These data identify a multisynaptic circuit of neurones in the spinal cord and in the brain which may be involved in the control of testicular functions.

Detection of DNA curvature by transverse pore gradient gel electrophoresis on PhastSystem gels

It has been known since 1990 that DNA curvature can be recognized on transverse pore gradient gels by an intersection of "Ferguson curves" with those of DNA size standards. The miniaturized PhastSystem polyacrylamide gels allow one to detect DNA curvature effortlessly and fast and at great economy of sample relative to alternative methods of electrophoresis. Using the transverse gradient gel electrophoresis method, it was found that the 660 bp length subfragment of the matrix attachment region (MAR) sequence of the chicken lysosyme gene migrates as a fragment of 800-900 bp length. When subjected to digestion with the restriction enzyme HaeIII, the fragment gives rise to two species of 248 and 412 bp length, respectively. The Ferguson curves of both species intersect with those of DNA size standards, indicating that both exhibit curvature. Only the curvature of the 412 bp fragment conforms to prediction. Ethidium bromide abolishes the effect of curvature on the fragment, reducing its apparent size from 900 to 660, the value obtained by agarose gel electrophoresis.

Lacrimal preganglionic neurons form a subdivision of the superior salivatory nucleus of rat: transneuronal labelling by pseudorabies virus

Transneuronal viral tracing was applied to localize preganglionic parasympathetic neurons in the brainstem which innervate the extraorbital lacrimal gland in the rat. The Bartha strain of pseudorabies virus was injected into the lacrimal gland, and after different survival times, the superior cervical and Gasserian ganglia, the upper thoracic spinal cords and the brainstems were immunostained by antiviral antiserum. Virus-labelled neurons appeared in the ganglia and in the ventrolateral part of the ipsilateral brainstem at the pontomedullary junction 45 h after inoculation. The virus-labelled brainstem neurons comprised a subgroup of the superior salivatory nucleus (SSN) located between the root fibers of the facial nerve and the nuclei of the superior olive, and were clearly distinguished from the tyrosine hydroxylase (TH)-immunopositive, A5 catecholaminergic neurons by double immunostaining. The number of infected cells in the ipsilateral SSN was increased by 72 h, and labelled neurons appeared in the intermediolateral cell column (IML) of the ipsilateral thoracic spinal cord. In rats with cervical ganglionectomy prior to the virus injection in the lacrimal gland, virus-infected cells appeared in the SSN, but not in the thoracic spinal cord, indicating that preganglionic SSN cells were infected via parasympathetic axons of the facial nerve. A double-virus tracer labelling technique was applied to determine the topographical relationship between the preganglionic parasympathetic neurons of the lacrimal gland and those of the submandibular gland within the SSN. Simultaneous injection of Bartha strain of pseudorabies virus into the submandibular gland, and a lacZ gene-containing Bartha-derived virus strain into the lacrimal gland (and vice versa) demarcated a ventral lacrimal and a dorsal submandibular subgroup in the SSN.

Neuronal labeling in the rat brain and spinal cord from the ovary using viral transneuronal tracing technique

In the present investigations the viral transneuronal labeling method, which is able to reveal hierarchial chains of central nervous system (CNS) neurons, was applied to identify sites in the CNS connected with the ovary and presumably involved in the control of ovarian functions. Pseudorabies virus was injected into the ovaries of rats and a few days later (at various times after the injection) the spinal cord and brain were examined for virus-infected neurons from the ovary. The virus-labeled nerve cells were identified by immunocytochemistry using polyclonal antiviral antibody. Virus-labeled neurons were detected both in the spinal cord and the brain. In the spinal cord such elements were observed in the intermediolateral cell column, in the dorsal horn close to the marginal zone and in the central autonomic nucleus. In the medulla oblongata and pons, neurons of several nuclei and cell groups (area postrema, nucleus of the solitary tract, dorsal vagal complex, nucleus ambiguus, paragigantocellular nucleus, parapyramidal nucleus, A1, A5 and A7 cell groups, caudal raphe nuclei, locus ceruleus, subceruleus nucleus, Barrington's nucleus, Kölliker-Fuse nucleus) were found to be transneuronally labeled. In the mesencephalon, the ventrolateral part of the periaqueductal gray matter contained virus-labeled neurons. In the diencephalon, a very intensive cell body labeling was observed in the hypothalamic paraventricular nucleus and a few virus-infected neurons could be detected in the lateral and dorsal hypothalamus, in the arcuate nucleus, zona incerta, perifornical area and in the anterior hypothalamus. Concerning the telencephalic structures, virus-labeled cells were found in the bed nucleus of the stria terminalis and in the central amygdala nucleus. These findings provide the first neuromorphological evidence for the existence of a multisynaptic neuronal pathway between the ovary and the CNS, and give a detailed account of the structures involved in this pathway.