Résumé
This study is to set up a method for separating,culturing and identifying neural stem cells from cortex in rat embryo,observing their characteristics of multipotentiality and differentiation in vitro. By using serum-free cell culturing and clone technology,the stem cells were isolated,cultured and passaged from cortex in 14-day old rat embryo. The expression of Nestin antigen of brain cells were investigated by immunocytochemistry and H-E staining. It proved that cells separated from cortex in rat embryo possessed the potential to form clones and express nestin special antigen,the differentiated cells could express special antigen of neurons,astrocytes,and oligodendrocytes,they were stem cells of central nervous system.
Résumé
The effects of electrical stimulation of spinal cord and nucleus tractus solitarius (NTS) on unit activity of paraventricular neucleus (PVH) in the rats were studied. The results of experiments in 105 rats showed that in the 1365 units, 67 units made responses to electrical stimulation of spinal cord, and 42 units to electrical stimulation of nucleus tractus solitarius.In the 67 units responsive to electrical stimulation of spinal cord, five kinds of ffects were observed: facilitatory, excitatory, inhibitory, inhibitory-excitatory and excitatory-inhibitory. In the 42 units responsive to electrical stimulation of nucleus ractus solitarius some showed facilitatory effects and others inhibitory effects.The results indicate that the majority of spinal inputs is conveyed to the PVH along multisynaptic pathways,while a lesser part along oligo-or mono-synaptic pathways.The results also suggest that there are multisynaptic pathways from rostral part of nucleus tractus solitarius to the PVH.
Résumé
Effects of microiontophoretically applied transmitter receptor antagonists on the evoked response of “pain” units of PVN in rats by sciatic stimulation were observed. The results showed: (l)The evoked response of 7 out of 38 PVN “pain” units could be blocked by atropine (7/38); 5 out of 27 by hexamethonium; 6 out of 31 by phentolamine (6/31); and 4 out of 25 by propranolol (4/25). Seventeen out of 52 were blocked by cyproheptadine (17/52), but 3 out of 52 were augmented by cyproheptadine (3/52). (2) The evoked response of the same “pain” unit could be blocked by two antagonists: the evoked response of 2 out of 27 PVN “pain” units could be blocked by atropine and cyprohepadine; 3 out of 20 by hexamethonium and cyproheptadine; 2 out of 25 by prepamolol and cyproheptadine. These results suggest that the noxious somatic input to PVN involves 5-HT, cholinergic and adrenergic transmitter receptor mechanisms and that the convergence of various transmitter systems on PVN “pain” unit is indicated.