Neuroscience research
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Neuroscience research · Jun 1994
Comparative StudyDistribution of corticotropin-releasing factor and calcitonin gene-related peptide in the developing mouse cerebellum.
Corticotropin-releasing factor (CRF)-like immunoreactive (IR) fibers were investigated ontogenically in the mouse cerebellum. CRF-IR was detected in the climbing fiber and mossy fibers as in other species. In addition, CRF-IR dense fiber plexuses were detected from postnatal day (PD) 2 to 9, in the developing Purkinje cell layer of the vermal lobules, paraflocculus, flocculus and crus 1 ansiform lobule, gradually forming a pericellular nest around the Purkinje cell somata. ⋯ No neurons containing both CRF and CGRP immunoreactivities were observed. These results suggest that CGRP- and CRF-IR developing climbing fibers innervate different compartments of Purkinje cells, especially in the vestibular cerebellar cortex in mice. Furthermore, CRF-IR fibers gradually changed to become typical climbing fibers, while CGRP-IR disappeared altogether.
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Neuroscience research · Dec 1993
A whole cell patch-clamp study on the pacemaker potential in dopaminergic neurons of rat substantia nigra compacta.
A whole-cell patch-clamp recording was obtained from dopamine (DA) neurons (n = 68) in the substantia nigra compacta (SNc) in in vitro slice preparations in order to study the underlying current for pacemaker-like slow depolarization (PLSD) which was considered as a basis for rhythmic firing of DA neurons. SNc DA neurons were identified immunohistochemically after recording. ⋯ The amplitude of Ip produced by a command pulse stepped to -50 mV from a holding potential of -80 mV was -78 +/- 42 pA (n = 23). (5) The threshold for activation of transient Ca2+ current (IT) was around -70 to -65 mV and inactivated completely at -70 to -65 mV (n = 11). The peak amplitude of IT evoked at -60 to -55 mV from a holding potential of more negative than -80 mV was 489 +/- 170 pA (n = 11). (6) The decay time constant of IT was 28 +/- 12 ms at -60 mV (n = 8) and that of IP was 2.35 +/- 1.37 s at -50 mV (n = 11) when recorded with a pipette containing 10 mM EGTA and 140 mM CsCl. (7) The decay of IP was apparently accelerated by decreasing the concentration of EGTA in the pipette solution from 10 to 1 mM.(ABSTRACT TRUNCATED AT 400 WORDS)
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Neuroscience research · Oct 1992
Distribution and origin of extrinsic nerve fibers containing calcitonin gene-related peptide, substance P and galanin in the rat upper rectum.
The distributions of nerve fibers containing calcitonin gene-related peptide (CGRP), substance P (SP) and galanin (GAL) were examined in the rat rectum of mutants rats, aganglionic rats (AGRs), which completely lack the intramural nerve cells in the large intestine, and of their normal littermates. The origin of extrinsic peptide-containing nerve fibers was examined using retrograde tracing combined with immunohistochemistry in normal rats. In the rectum of normal rats, CGRP-, SP- and GAL-immunoreactive varicose fibers were observed throughout all layers of the rectal wall, and immunoreactive nerve cells were present in the enteric ganglia of colchicine-treated rats. ⋯ Comparison of serial sections of the dorsal root ganglion revealed that about half of the CGRP-immunoreactive cells were also positive for SP or GAL. These results indicate that SP- or GAL-positive neurons projecting to the rectum are scarce in the dorsal root ganglia. The present investigation suggests that CGRP-containing nerves are visceral afferents forming a major component of the sensory innervation of the rat rectum, and SP- and GAL-containing nerves which share their extrinsic origins appear to form a lesser proportion of the sensory innervation.
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Neuroscience research · Feb 1984
Superior vestibular nucleus neurones related to the excitatory vestibulo-ocular reflex of anterior canal origin and their ascending course in the cat.
Stimulation of the superior vestibular nucleus and the anterior canal nerve evoked mono- and disynaptic excitatory postsynaptic potentials, respectively, in contralateral inferior oblique motoneurones of the cat. Combined stimulation revealed that the superior vestibular nucleus relayed excitatory anterior canal signals to the motoneurones. Thirty-six superior vestibular neurones receiving anterior canal inputs were activated antidromically by microstimulation of the contralateral inferior oblique motoneurone pool. Their axons ascended neither in the brachium conjunctivum nor in the medial longitudinal fasciculus, but proceeded rostrally in the ventral part of the brain stem.