NADPH-d activity in rat thymus after the application of retinoid acid.

The aim of this work was to determine the localization of nicotinamide-adenine dinucleotide phosphate-diaphorase (NADPH-d) activity as the marker for synthesis of nitric oxide synthase (NOS) in the rat thymus after the application of retinoid acid (RA) on 1st, 7th, 14th and 21st days of gestation. The given results can build the basis for understanding of the role of NOS in rat thymus. NADPH-d positive cells were represented with dark-blue color and were localized on corticomedullar junction of the thymus. These cells were of different intensity of coloring and were shaped in oval, circle or irregular forms. NADPH-d positive nerve fibers were observed in perivascular topography. They were marked more strongly in the case of control group. The result of application of RA to gravid rats was that the birth weights of newborn rats and their thymuses were smaller, but without statistically significance.

Influence of surgical and chemical orchidectomy on weight and distribution of AChE-nerve fibres in thymuses of adult rats.

The thymus is a crossroad between the immune and neuroendocrine systems. As such, it is innervated by acetylcholinesterase (AChE)-positive fibres of the vagus, the recurrent laryngeal and the phrenic nerves. It is well know, that the innervations density of the thymus increases with age. In our study, adult rats were orchidectomized (surgically and chemically by the application of a luteinizing hormone-releasing hormone). The density of AChE-positive nerve fibres in thymuses, as well as the weight of thymuses was examined. The authors found that both surgical and chemical orchidectomy result in macroscopic and microscopic regeneration of the atrophied thymuses. In regenerated rat's thymuses after orchidectomy the density of AChE-positive nerve fibres was markedly higher in comparison with the control animals. The distribution, as well as the density of AChE-positive nerve fibres in regenerated thymuses after orchidectomy evokes the images of its innervations like in young animals before age-related involution. The authors also found a markedly higher weight of thymuses of orchidectomized rats in comparison with the control groups. In recent study the authors proved that after 8 weeks surgical orchidectomy leads to the regeneration of thymic AChE-positive innervation and chemical orchidectomy by administration of luteinizing hormone-releasing hormone after 4 weeks of adult rats.

Distribution of NADPH-diaphorase and AChE activity in the anterior leaflet of rat mitral valve.

The mitral valve, as an active flap, forms the major part of the left ventricular inflow tract and therefore plays an important function in many aspects of left ventricular performance. The anterior leaflet of this valve is the largest and most ventrally placed of two leaflets that come together during ventricular systole to close the left atrioventricular orifice. Various neurotransmitters are responsible for different functions including controlling valve movement, inhibiting or causing the failure of impulse conduction in the valve and the sensation of pain. Nitric oxide acts as a gaseous free radical neurotransmitter, neuromediator and effective cardiovascular modulator. Acetyl-choline is known to function as a typical neurotransmitter. Histochemical methods for detection of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d), as an indirect nitric oxide-synthase marker, and method for detection of acetylcholinesterase (AChE) were used. Both methods were performed on the same valve sample. A widespread distribution of nerve fibres was observed in the anterior leaflet of the mitral valve. The fine NADPH-d positive (nitrergic) nerve fibres were identified in all zones of valve leaflet. AChE positive (cholinergic) nerve fibres were identified forming dense network and fibres organized in stripes. Endocardial cells and vessels manifested heavy NADPH-d activity. Our observations suggest a different arrangement of nitrergic and cholinergic nerve fibres in the anterior leaflet of the mitral valve. The presence of nitrergic and cholinergic activity confirms the involvement of both neurotransmitters in nerve plexuses and other structures of mitral valve.

Alterations of the vessel wall innervation during diabetes mellitus.

Coronary and valvular heart disease during diabetes mellitus (DM) are major contributors of morbidity and mortality in the diabetic population. Relatively little atention has been given to the study of heart valve nerve structures in different pathological processes. In this study we have demonstrated the presence of possible morphological alterations in vessels of the anterior cusp of the rat mitral valve during 8-12 weeks DM. A histochemical method was used for the detection of NADPH-diaphorase (NADPH-d), which is the indirect NO-synthase marker. Arterioles and fine capillaries were localized in the attachment zone of the anterior cusp. Perivascular nerve fibres were identified running in the tunica adventitia. A marked dilatation of the vessels was seen in diabetes in comparison with control samples. No NADPH-d positive nerve fibres were observed in the tunica adventitia. It can be presumed that metabolic changes in the vessel walls during DM reflect modified neurotransmission of NO by means of their excessive overproduction of NOS (endothelial--eNOS) in endothelial cells. (Fig. 6, Ref. 32.).

Comparative analysis of NADPH-diaphorase positive neurons in the rat, rabbit and pheasant thoracic spinal cord. A histochemical study.

The distribution of NADPH-diaphorase (NADPH-d) activity was investigated and compared in the rat, rabbit and pheasant thoracic spinal cord. The investigation of all spinal cord regions (laminae) in three experimental species revealed marked differences in the distribution of NADPH-d activity. Cross sectional analysis of the spinal cord of the rat, rabbit and pheasant confirmed differences in the shape of the gray matter in all examined species. More detailed investigation of Rexed's laminas showed similar distribution of NADPH-d activity in the spinal cord of the rat and rabbit, which were different when compared with the spinal cord of the pheasant. Ventral horn of the rat and rabbit showed no labelling whereas in pheasant this area possessed a number of scattered, intensively stained neurons. In the location of autonomic preganglionic neurons, differences were found as well. In the rat there was seen a number of densely packed, clearly dark blue coloured neurons. Similarly, these neurons were present in the rabbit spinal cord but they were less numerous. No staining was found in this region of pheasant. Pericentral area (lamina X) and intermediate zone (laminaVII) revealed the presence of NADPH-d positive neurons in all examined species although they differed in number and shape of their bodies. The dorsal horn showed the presence of NADPH-d staining in all three animals but its distribution was different in medio-lateral direction. It can be suggested that observed differencies in the presence and distribution of NADPH-d activity across the examined species may reflect different fylogenetic development.

[Detection of peptidergic and nitrergic structures in the spinal ganglia of rabbits]. / Dôkaz prítomnosti peptidergických a nitrergických struktúr v spinálnych gangliách králika.

In this study we have demonstrated the presence of neuropeptide substance P and non-peptide neurotransmitter NO (nitric oxide) in the dorsal root ganglia of rabbit. NADPH-diaphorase histochemical staining was used for the detection of NO and immunohistochemical method for the detection of substance P.A particular number of dorsal root ganglion (DRG) cells were stained by SP and NADPH-d reaction. The presence of SP and NADPH-diaphorase positive cells varied depending upon spinal level of DRGs. Positively stained neurons were only small or medium-sized. Cells of large diameter profiles showed no staining. Substance P immunoreactive cells were stained brown and dark brown, the intensity of NADPH-d staining varied from light to very dark blue. In some DRGs cells, there was a very significant neuronal co-localization of immunoreactivity for SP and reactivity for NADPH-d. In summary, DRG cells appear to express diaphorase and substance P activity, and some of them contain both neurotransmitters. Recent studies analysing the participation of NO in the regulation of SP release in the spinal cord suggest, that the DRGs neurons may display a close interaction between NO and SP. (Fig. 14, Ref. 39.)

[Coexistence of cholinergic and nitrergic neurotransmitters in the spinal cord of rabbits]. / Koexistencia cholínergického a nitrergického neurotransmitera v mieche králika.

Nitric oxide (NO) plays a major role as a neuronal messenger molecule. NO has been assumed to act as a retrograde signalling molecule that modulates transmitter release. Acetylcholine (ACh) is known to function as a typical neurotransmitter. In the present work the presence of both transmitters (NO and ACh) and their possible relations in the rabbit spinal cord were examined. In our experiments histochemical methods for the visualisation of acetylcholinesterase (AChE) and NADPH diaphorase (NADPH-d) were used. Both histochemical methods were performed separately and together on the same sections of the thoracic spinal cord. NADPH-d positive dark blue stained neurons were mainly detected in superficial and deep layers of dorsal horn, preganglionic autonomic neurons and pericentral area (1). The presence of AChE positive amber yellow neurons was confirmed mostly in motoneurons located in ventral horns and then in neurons of the intermediate zone. Except for the above mentioned also double-labeled neurons containing both yellow and dark blue histochemical product were noticed. Their presence was confirmed in the intermediate zone and in the pericentral area. Thus, the coexistence of NADPH-d and AChE was confirmed in the area of interneurons. These observations suggest that NO may play a role in the control of cholinergic neuronal activity and that NO can be involved in the modulation of synaptic transmission. (Fig. 9, Ref. 21.)

Partial colocalization of NADPH-diaphorase and acetylcholinesterase positivity in spinal cord neurons.

The freely diffusible radical, nitric oxide (NO), has been assumed to act as a retrograde signaling molecule that modulates transmitter release. Acetylcholine (ACh) is known to function as a typical neurotransmitter. In the present work we have examined the presence of both transmitters (NO and ACh) and their possible relations in the rabbit spinal cord. In our experiments we have used histochemical methods for the visualization of acetylcholinesterase (AChE) and NADPH diaphorase (NADPH-d) which label neurons that express nitric oxide synthase (NOS). Both histochemical methods were performed separately or together on the same sections of the thoracic spinal cord. NADPH-d positive dark blue stained neurons were seen mostly in superficial and deep layers of the dorsal horn, preganglionic autonomic neurons and pericentral area. The presence of AChE positive amber yellow neurons was confirmed mostly in motoneurons located in the ventral horns and in neurons of the pericentral and intermediate zone. Besides the above mentioned neurons, also double-labeled neurons were found which contained both the yellow and dark blue histochemical product. Their presence was confirmed in the intermediate zone and in the pericentral area. Thus, the co-existence of NADPH-d and AChE occurred in the location of interneurons. Our observations suggest that NO may play a role in the control of cholinergic neuronal activity and that NO can be involved in the modulation of synaptic transmission.

[Laminar distribution of NADPH-diaphorase in the thoracic spinal cord in pheasants]. / Laminárna distribúcia NADPH-diaforázy v hrudníkovej mieche bazanta.

BACKGROUND: The distribution of NADPH-diaphorase (NADPH-d) activity was investigated in the spinal cord of pheasants. MATERIAL AND METHODS: Histochemical method for visualization of NADPH-d was used in this study. This method is considered to be a good marker for NO synthase. RESULTS: The investigation of NADPH-d activity in laminae of the thoracic spinal cord of pheasants revealed the presence of scattered intensively stained neurons in laminae VIII and IX of the ventral horn. In the location of autonomic preganglionic neurons, no presence of NADPH-d positivity was noticed. The pericentral area (lamina X) and intermediate zone (lamina VII) showed NADPH-d positive neurons located more dorsally with larger distance from the central canal. In superficial layers of the dorsal horn (lamina I and II) marked differences were seen in the distribution of NADPH-d activity through the medio-lateral direction. CONCLUSION: In summary, it can be suggested that the observed presence of NADPH-d activity may reflect the utilization of NO in the thoracic part of the spinal cord in pheasants. (Fig. 5, Ref. 20.)

Expression of peptidergic and nitrergic structures in dorsal root ganglia of the rabbit.

In this study we have demonstrated the presence of neuropeptide substance P (SP)and nonpeptide neurotransmiter NO (nitric oxide) in the dorsal root ganglia (DRG) of rabbits. NADPH-diaphorase histochemical staining was used for detection of NO and an immunohistochemical method for detection of substance P. A number of DRG cells were stained by SP- and NADPH-d reactions. The presence of SP and NADPH-diaphorase positive cells varied depending upon the spinal level of the DRG. Positively stained neurons were only small and intermediate in size. Cells of large diameter profiles showed no staining. Substance P immunoreactive cells were of brown and dark brown colour, the intensity of NADPH-d staining varied from light to very dark blue. In some DRG cells, there was very significant neuronal co-localization of immunoreactivity for SP and reactivity for NADPH-d. In summary, DRG cells appear to express diaphorase and substance P activity, and some of them show the presence of both neurotransmitters. Recent studies on the participation of NO in the regulation of SP release in the spinal cord suggest, that also in the DRG neurons there may be a close interaction between NO and SP.

Relative pathogenicity of Candida tropicalis in rat tongue mucosa.

The potential of C. tropicalis to colonize and infect rat tongue mucosa was demonstrated. Thirty female Sprague-Dawley rats were infected orally with three different strains of C. tropicalis. The animals were killed one and three weeks following the inoculation and sections of their tongue were stained with hematoxylin-eosin and Grocott stain. Histological changes were observed in the group of animals killed one week after inoculation and infected with C. tropicalis strain isolated from the crural ulcer of a diabetic patient. The most important finding was acute purulent myositis with the formation of abscesses. The myositis was local without signs of spreading to the surrounding tissue. Epithelium-penetrating hyphae observed in the Grocott-stained sections were relatively fewer and more sparsely distributed.

[Variation in the localization of NADPH-d positive neurons in the gray matter of the spinal cord in different species]. / Odlisnosti v lokalizácii NADPH-d pozitívnych neurónov v sivej hmote miechy jednotlivých druhov.

The presence of NADPH-diaphorase (NADPH-d) activity was investigated in the thoracic part of rat, rabbit and pheasant spinal cords. Histochemical method for visualization of NADPH-d was used in this study. The comparison between all spinal cord regions (laminae) in three experimental species revealed marked differences. Especially in the ventral horn, the presence of NADPH-d activity was different. While the pheasant ventral horn possessed number of scattered intensively stained neurons, the rat and rabbit showed no NADPH-d activity in this region. Pericentral area (lamina X), intermediate zone (lamina VII) and dorsal horn revealed the presence of NADPH-d positive neurons in all examinated species although they differed in the distribution of NADPH-d activity. In summary, it can be suggested that the observed differences in the presence and distribution of NADPH-d activity among species may reflect their different phylogenetic development. As a consequence, different NO function in spinal cord of various species can be presumed. (Fig. 10, Ref. 28.)

[Nitrergic structures in the spinal ganglia in rabbits]. / Nitrergické struktúry v spinálnych gangliách králika.

Nitrergic structures in normal rabbit dorsal root ganglia (DRG) were demonstrated in this study. Histochemical reaction for detection of NADPH-d activity was used indicating, the presence of nitric oxide synthase (NOS). Diaphorase activity was found mostly in small ganglion cells. The cells defined as intermediate in size were stained less frequently, and no big cell expressed diaphorase activity. The intensity of staining varied from light blue and violet to very dark. The highest number of reactive cells was detected in the sacral DRG. Neurons expressed very low concentration of diaphorase activity in cervical, thoracic and lumbar DRGs. These findings suggest, that NADPH-diaphorase activity demonstrate a distinctive distribution depending upon spinal level.