OBJECTIVETo investigate the growth and development of nerve growth factor (NGF)-positive neurons in the cerebellum of midanaphase human fetus.

METHODSThe expression of the NGF-positive neurons in the cerebrum of human fetus was observed by immunohistochemical methods, and the integral absorbance (IA) was detected.

RESULTSBy the 3rd to 4th month of gestation, neurons was seen in the ependymal, central, and marginal plate of cerebellum; the nucleus was oval and the neurons had short and small processes. By the 5th to 7th month of gestation, the number of NGF-positive neurons increased, the expressions enhanced, the nucleus was round-, oval-, or fusiform-shaped, the neurons grew larger in size, and the Purkinje cells showed NGF-positive expression. By the 8th to 10th month of gestation, the NGF-positive expression was enhanced with deeper dying, the body of Purkinje cells grew larger gradually, and the number of NGF-positive neurons in the granular cell layer and molecular layer increased. IA of the cerebellar cortical neurons of the 3rd, 4th, 5th, 6th, 7th, and 8th month of gestation showed an increasing trend, and significant difference was observed (P < 0. 05).

CONCLUSIONNGF-positive neurons in the cerebellum play an important role for differentiation, proliferation, migration, and growth of neurons in the cerebellum.

Cerebellum ; cytology ; metabolism ; Fetus ; cytology ; metabolism ; Humans ; Nerve Growth Factor ; metabolism ; Neurons ; cytology ; metabolism ; Purkinje Cells ; metabolism

OBJECTIVE: To investigate the variations in the expression of voltage-gated sodium (Na_v) channel subunits during development of rat cerebellar Purkinje neurons and their correlation with maturation of electrophysiological characteristics of the neurons. METHODS: We observed the changes in the expression levels of Na_V1.1, 1.2, 1.3 and 1.6 during the development of Purkinje neurons using immunohistochemistry in neonatal (5-7 days after birth), juvenile (12-14 days), adolescent (21-24 days), and adult (42-60 days) SD rats. Using whole-cell patch-clamp technique, we recorded the spontaneous electrical activity of the neurons in ex vivo brain slices of rats of different ages to analyze the changes of electrophysiological characteristics of these neurons during development. RESULTS: The expression of Na_V subunits in rat cerebellar Purkinje neurons showed significant variations during development. Na_V1.1 subunit was highly expressed throughout the developmental stages and increased progressively with age (P < 0.05). Na_V1.2 expression was not detected in the neurons in any of the developmental stages (P > 0.05). The expression level of Na_V1.3 decreased with development and became undetectable after adolescence (P < 0.05). Na_V1.6 expression was not detected during infancy, but increased with further development (P < 0.05). Na_V1.1 and Na_V1.3 were mainly expressed in the early stages of development. With the maturation of the rats, Na_V1.3 expression disappeared and Na_V1.6 expression increased in the neurons. Na_V1.1 and Na_V1.6 were mainly expressed after adolescence. The total Na_V protein level increased gradually with development (P < 0.05) and tended to stabilize after adolescence. The spontaneous frequency and excitability of the Purkinje neurons increased gradually with development and reached the mature levels in adolescence. The developmental expression of Na_V subunits was positively correlated with discharge frequency (r=0.9942, P < 0.05) and negatively correlated with the excitatory threshold of the neurons (r=0.9891, P < 0.05). CONCLUSION The changes in the expression levels of Na_V subunits are correlated with the maturation of high frequency electrophysiological properties of the neurons, suggesting thatmature Na_V subunit expressions is the basis of maturation of electrophysiological characteristics of the neurons.
Rats ; Animals ; Purkinje Cells/physiology* ; Rats, Sprague-Dawley ; Neurons ; Brain ; Sodium/metabolism*

Secretion of neurotransmitters is initiated by voltagegated calcium influx through presynaptic, voltage- gated N-type calcium channels. However, little is known about their cellular distribution in the mouse cerebellum. In the cerebellum, alpha1B immunoreactivity is found mainly on the cell bodies of all Purkinje cells. In addition, the immunoreactivity was detected on a subset of Purkinje cell dendrites, clustered to form a parasagittal array of bands. In the anterior lobe vermis, immunoreactive Purkinje cell dendrites form narrow stripes separated by broad bands of unstained dendrites. Moving caudally through the vermis, these stripes become thicker as a larger fraction of the Purkinje cell dendrites become immunoreactive. This localization study of the alpha1B pore-forming subunits in mouse cerebellum may guide future investigations of the role of calcium channels in neurological pathways.
Animals ; Calcium Channels, N-Type/*metabolism ; Cerebellum/cytology/*metabolism ; Dendrites/metabolism ; Immunohistochemistry ; Mice ; Mice, Inbred BALB C ; Purkinje Cells/metabolism

Cerebellar Purkinje cells (PCs) exhibit two types of discharge activities: simple spike (SS) and complex spike (CS). Previous studies found that noradrenaline (NA) can inhibit CS and bidirectionally regulate SS, but the enhancement of NA on SS is overwhelmed by the strong inhibition of excitatory molecular layer interneurons. However, the mechanism underlying the effect of NA on SS discharge frequency is not clear. Therefore, in the present study, we examined the mechanism underlying the increasing effect of NA on SS firing of PC in mouse cerebellar cortex in vivo and in cerebellar slice by cell-attached and whole-cell recording technique and pharmacological methods. GABA_A receptor was blocked by 100 µmol/L picrotoxin in the whole process. In vivo results showed that NA significantly reduced the number of spikelets of spontaneous CS and enhanced the discharge frequency of SS, but did not affect the discharge frequency of CS. In vitro experiments showed that NA reduced the number of CS spikelets and after hyperpolarization potential (AHP) induced by electrical stimulation, and increased the discharge frequency of SS. NA also reduced the amplitude of excitatory postsynaptic current (EPSC) of parallel fiber (PF)-PC and significantly increased the paired-pulse ratio (PPR). Application of yohimbine, an antagonist of α2-adrenergic receptor (AR), completely eliminated the enhancing effect of NA on SS. The α2-AR agonist, UK14304, also increased the frequency of SS. The β-AR blocker, propranolol, did not affect the effects of NA on PC. These results suggest that in the absence of GABA_A receptors, NA could attenuate the synaptic transmission of climbing fiber (CF)-PC via activating α2-AR, inhibit CS activity and reduce AHP, thus enhancing the SS discharge frequency of PC. This result suggests that NA neurons of locus coeruleus can finely regulate PC signal output by regulating CF-PC synaptic transmission.
Action Potentials/physiology* ; Animals ; Cerebellar Cortex/metabolism* ; Cerebellum/metabolism* ; Mice ; Norepinephrine/pharmacology* ; Purkinje Cells/metabolism* ; Receptors, Adrenergic, alpha-2/metabolism* ; Receptors, GABA-A/metabolism*

Sparse labeling of neurons contributes to uncovering their morphology, and rapid expression of a fluorescent protein reduces the experiment range. To achieve the goal of rapid and sparse labeling of neurons in vivo, we established a rapid method for depicting the fine structure of neurons at 24 h post-infection based on a mutant virus-like particle of Semliki Forest virus. Approximately 0.014 fluorescent focus-forming units of the mutant virus-like particle transferred enhanced green fluorescent protein into neurons in vivo, and its affinity for neurons in vivo was stronger than for neurons in vitro and BHK21 (baby hamster kidney) cells. Collectively, the mutant virus-like particle provides a robust and convenient way to reveal the fine structure of neurons and is expected to be a helper virus for combining with other tools to determine their connectivity. Our work adds a new tool to the approaches for rapid and sparse labeling of neurons in vivo.
Animals ; Cells, Cultured ; Gene Expression ; Genetic Vectors ; genetics ; metabolism ; Green Fluorescent Proteins ; genetics ; metabolism ; Immunohistochemistry ; methods ; Male ; Mice, Inbred C57BL ; Microscopy, Fluorescence ; methods ; Neurons ; cytology ; metabolism ; Purkinje Cells ; cytology ; metabolism ; Semliki forest virus ; genetics