大鼠胰岛内γ-干扰素样免疫反应阳性物质的表达

In order to study the correlation between the neuroendocrine and immune systems, we observed the distribution and expression of interferon γ(IFN-γ) in cells of SD rat pancreas islets using the streptavidin-perosidase immunohistoche-mical method. A number of IFN-γ-like positive substances were found in the in the cytoplasm of pancreas islet A cells, but the nucleus could not be stained. Most of the IFN-γ-like positive cells were distributed around the periphery of the pan-creas islet, the cells were round or oval in shape and the cell body was relatively large. Results suggest IFN-γ may play a role in the regulation of the function of pancreas islet cells and act as a neuro-immune medium.     

Application of the sodium hyaluronate-CNTF scaffolds in repairing adult rat spinal cord injury and facilitating neural network formation

The present study aimed to explore the potential of the sodium hyaluronate-CNTF (ciliary neurotrophic factor) scaffold in activating endogenous neurogenesis and facilitating neural network re-formation after the adult rat spinal cord injury (SCI). After completely cutting and removing a 5-mm adult rat T8 segment, a sodium hyaluronate-CNTF scaffold was implanted into the lesion area. Dil tracing and immunofluorescence staining were used to observe the proliferation, differentiation and integration of neural stem cells (NSCs) after SCI. A planar multielectrode dish system (MED64) was used to test the electrophysiological characteristics of the regenerated neural network in the lesioned area. Electrophysiology and behavior evaluation were used to evaluate functional recovery of paraplegic rat hindlimbs. The Dil tracing and immunofluorescence results suggest that the sodium hyaluronate-CNTF scaffold could activate the NSCs originating from the spinal cord ependymal, and facilitate their migration to the lesion area and differentiation into mature neurons, which were capable of forming synaptic contact and receiving glutamatergic excitatory synaptic input. The MED64 results suggest that functional synapsis could be established among regenerated neurons as well as between regenerated neurons and the host tissue, which has been evidenced to be glutamatergic excitatory synapsis. The electrophysiology and behavior evaluation results indicate that the paraplegic rats’ sensory and motor functions were recovered in some degree. Collectively, this study may shed light on paraplegia treatment in clinics.     

Comparison of dark- and light-adapted carp retinas with NADPH diaphorase staining

The carp retina was examined by NADPH diaphorase histochemistry to determine if the staining pattern of retinal cells was changed depending on the adaptation state of the retina. When dark-adapted for 5 h, ellipsoids of inner segments of both rods and cones and some horizontal cells were heavily stained. Staining was also found in subpopulations of amacrine cells and ganglion cells. In addition, Muller cells were strongly positive for NADPH diaphorase. When light-adapted for 5h, ellipsoids of photoreceptors and ganglion cells were less intensely stained, whereas Muller cells and horizontal cells became negative for NADPH diaphorase. Furthermore, rod ON-center bipolar cells were clearly stained. The difference of staining of amacrine cells between dark- and light-adapted retinas was not significant. The differences in diaphorase-staining pattern between dark- and light-adapted retinas suggest that Muller cells, some horizontal cells and rod ON-center bipolar cells contain inducible nitric oxide synthase,     

Mediation by calcium/calmodulin-dependent protein kinase II of suppression of GABA_A receptors by NMDA

Using nystatin-perforated whole-cell recording configuration, the modulatory effect of N-methyl-D-aspartate (NMDA) on γ-aminobutyric acid (GABA)-activated whole-cell currents was investigated in neurons freshly dissociated from the rat sacral dorsal commissural nucleus (SDCN). The results showed that: (i) NMDA suppressed GABA- and muscimol (Mus)-activated currents (IGABA and IMUS), respectively in the Mg2 -free external solution containing 1 μmol/L glycine at a holding potential (VH) of -40 mV in SDCN neurons. The selective NMDA receptor antagonist, D-2-amino-5-phosphonovaleric acid (APV, 100 μmol/L), inhibited the NMDA-evoked currents and blocked the NMDA-induced suppression of IGABA; (ii) when the neurons were incubated in a Ca2 -free bath or pre-loaded with a membrane-permeable Ca2 chelator, BAPTA AM (10 nmol/L), the inhibitory effect of NMDA on IGABA disappeared. Cd2 (10 μmol/L) or La3 (30 μmol/L), the non-selective blockers of voltage-dependent calcium channels, did not affect the suppressio     

Physiological properties of neurons in superficial layers of superior colliculus of rabbits

Neurons in superficial layers of the superior colliculus of the rabbit are classified into three types by their electrophysiological properties. Among them, two types belong to projecting neurons which send axons to the thalamic pulvinar (N=52) and dorsal lateral geniculate nucleus (N = 54) respectively. All other neurons are pooled into the third type (N=99). Projecting neurons of both types receive monosynaptic visual inputs via optic tract fibers of similar conduction velocity, indicating that in the superior colliculus of the rabbit, there is no difference in conduction velocity between the two pathways. They also receive trisynaptic inhibitory inputs, most likely via recurrent inhibitory circuits. The third type of neurons receives disynaptic optic and trisynaptic inhibitory inputs. The function of neurons of the third type is studied.     

Influences of cerebellar interpositus nucleus and fastigial nucleus on neuronal activity of lateral hypothalamic area

Stimulation of cerebellar interpositus nucleus and (astigial nucleus could influence the neuronal activi-ty of lateral hypothalamic area in the cat, and some of the neurons which respond to the cerebellar stimulations are glucose-sensitive neurons. These results suggest that the cerebellum is involved not only in motor control, but also in the regulation of non-somatic functions through the cerebello-hypothalamic pathways.     

Neural correlates of behavioral gap detection in the inferior colliculus of the young CBA mouse

The gap detection paradigm is frequently used in psychoacoustics to characterize the temporal acuity of the auditory system. Neural responses to silent gaps embedded in white-noise carriers, were obtained from mouse inferior colliculus (IC) neurons and the results compared to behavioral estimates of gap detection. Neural correlates of gap detection were obtained from 78 single neurons located in the central nucleus of the IC. Minimal gap thresholds (MGTs) were computed from single-unit gap functions and were found to be comparable, 1–2 ms, to the behavioral gap threshold (2 ms). There was no difference in MGTs for units in which both carrier intensities were collected. Single unit responses were classified based on temporal discharge patterns to steady-state noise bursts. Onset and primary-like units had the shortest mean MGTs (2.0 ms), followed by sustained units (4.0 ms) and phasic-off units (4.2 ms). The longest MGTs were obtained for inhibitory neurons (xˉ = 14 ms). Finally, the time-course of behavioral and neurophysiological gap functions were found to be in good agreement. The results of the present study indicate the neural code necessary for behavioral gap detection is present in the temporal discharge patterns of the majority of IC neurons. Accepted: 6 February 1997     

The studies on neurogenesis indufced by brain injury in adult ring dove

It was the first time demonstrated by us that the number of newborn neurons was increased after making lesion in forebrain of adult ring dove(Streptopelia risoria) by means of autoradiography and imunohistochemistry,Neurogensis in the adult avian is restricted to the telencephalon.In doves with bilateral electrolytic lesion of nucleus ectostriatum(E),the mean mumber of proliferating cells in the lateral ventricular zone(LVZ) and newborn neurons in the forebrain increased by 1.95 times and 2.38 times respectively as compared with that in intact doves.The most remarkable incresase of neurogenesis induced by nucleus ectostriatum lesions was found at the anteriorposterior level 3(L3),where the lesion site was located.These results showed that the electrolytic brain lesion al tered the distribution pattern of proliferating cells in the LVZ and resulted in increase of the number of newborn neureons in the non-VZ areas of forebrain.The changes in number and distribution pattern of proliferating cells in LVZ and newbon neurons in forebrain may be dependent on site of lesion.Studies on the relationship between proliferating cells in LVZ and newly generated neurons in non-VZ aresa may help to understand the mechanism of brain plasticity and development.     

Synaptic organization of substance P, glutamate and GABA-immunoreactive boutons on functionally identified neurons in cat spinal deeper dorsal horn

In order to determine how nociceptive input conveyed by the C-fibers terminating in superficial lam-inae of the spinal cord reaches the wide dynamic range (WDR) cells in deeper dorsal horn, which functions as ascend-ing projection pathway, the morphological features of some WDR cells in the deeper dorsal horn of the cat lumbar spinal cord were studied by intracellular injection of horseradish peroxidase and physiological characterization. One of the fully stained neurons with somata in lamina V and dendrites that entered lamina Ⅱ were examined by electron mi-croscopy. Immunogold staining of ultrathin sections through the labeled proximal dendrites in lamina Ⅱ revealed that these dendrites received numerous synapses from substance P and glutamate immunoreactive (IR) axons, which were considered originating from C-fibers. In addition, many GABA-IR terminals were found presynaptic to the labeled dendrites. The results, therefore, suggest that the information carried by primary afferent can be sent from t     

猪圆环病毒2型及猪繁殖与呼吸综合症病毒的快速检测

According to the published genome sequences of Porcine circovirus type 2(PCV2)and Porcine reproductive and respiratory syndrome virus(PRRSV),primers were designed and PCR,RT-PCR were set up for the detection of PCV2 and PRRSV,respectively,With the established methods,38 clinical samples from the respiratory disease pigs were detected for the presence of PCV2 and PRRSV. The results demonstrated that 22 samples were positive for PCV2,27 samples were positive for PRRSV and among the above positive samples,18 samples were positive for both viruses,The data obtained in the present study indicated that PCV2 and PRRSV maybe play an important role in the course of the development of respiratiory diseases.