Koichi Noguchi

α-CGRP and β-CGRP mRNAs are differentially regulated in the rat spinal cord and dorsal root ganglion

Abstract We found an increase in calcitonin gene-related peptide (CGRP)-like immunoreactivity in motoneurons of rat spinal cord after peripheral axotomy. By means of in situ hybridization histochemistry and Northern blotting, we further demonstrated that this increase was the result of increased levels of α-CGRP mRNA, not β-CGRP mRNA. The increased level of α-CGRP mRNA was maintained for at least 5 weeks, and was present on both sides. In addition, α-CGRP and β-CGRP mRNAs had different distributions from each other in the dorsal root ganglia and levels of both were decreased after axotomy. These results indicate that α-CGRP and β-CGRP are regulated independently and have different roles in the motor and sensory systems of the spinal cord.

A noxious stimulus induces the preprotachykinin-A gene expression in the rat dorsal root ganglion: a quantitative study using in situ hybridization histochemistry

Using in situ hybridization histochemistry, we examined the biosynthesis of the preprotachykinin-A (PPTA) mRNAs, which code for substance P (SP) and also a related peptide, substance K (SK), in the rat dorsal root ganglion (DRG). The animals were injected with a small amount of formalin in the right hindpaw for nociceptive chemical stimulation. Analysis of hybridization signals in the emulsion autoradiography showed that the lumbar-5 DRG neurons expressing PPTA mRNAs were significantly increased in number and signal intensity on the formalin-injected side. Such elevation of the PPTA mRNA expression in the DRG was observed as early as 3 h after formalin injection. These results show that the expression of the PPTA gene is activated by chemogenic noxious stimuli.

Prepro-VIP and preprotachykinin mRNAs in the rat dorsal root ganglion cells following peripheral axotomy

Using in situ hybridization histochemistry, we examined the expression of prepro-vasoactive intestinal polypeptide (VIP) mRNAs and preprotachykinin (PPT) mRNAs which coded for substance P (SP) in the rat dorsal root ganglion (DRG) following spinal nerve transection. VIP mRNAs increased dramatically in the DRG neurons after transection of the peripheral branch of the spinal nerve (sciatic nerve), whereas PPT mRNAs showed a gradual decrease for a few weeks. Dorsal rhizotomy or axotomy of the central branch of DRG cells had little influence on VIP-mRNAs and no effect on PPT mRNA expression. These results demonstrated an activation of VIP biosynthesis in the DRG neurons due to axotomy of the peripheral branch, which was opposite to the reaction of PPT mRNA to the same treatment.

Operations for forearm deformity caused by multiple osteochondromas

We reviewed 36 cases of forearm deformity caused by multiple osteochondromas in 30 patients and classified them into three types: Type I showed a combination of ulnar shortening and bowing of the radius secondary to osteochondromas of the distal ulna (22 forearms). Type II showed dislocation of the radial head, either with osteochondromas of the proximal radius (Type IIa, two forearms) or secondary to more distal involvement (Type IIb, five forearms). Type III had relative radial shortening due to osteochrondromas at the distal radius (seven forearms). Operations were performed on 16 forearms in 13 patients, with 92% of satisfactory results. For Type I deformity, excision of osteochondromas, immediate ulnar lengthening and corrective osteotomy of the radius are recommended. For Type IIa, excision of the radial head is necessary, and for Type IIb, we advise gradual lengthening of the ulna using an external fixator. Excision of osteochondromas alone gave good results in Type III deformity. Our classification gives a reliable indication of the prognosis and is a guide to the choice of surgical treatment.

Effects of nerve crush and transection on mRNA levels for nerve growth factor receptor in the rat facial motoneurons.

We found that the level of nerve growth factor receptor (NGF-R) mRNA in facial motoneurons was increased after both facial nerve crushing and transection by means of in situ hybridization histochemistry. The increased level of NGF-R mRNA was maintained for at least 8 weeks after facial nerve transection, while facial nerve crushing caused only a transient increase. Thus, expression of NGF-R mRNA paralleled the axonal regeneration process. In addition, the increase of NGF-R mRNA with crushing was more pronounced than with transection from the 3rd to the 14th day after the insult.

Changes in expression of peptides in rat facial motoneurons after facial nerve crushing and resection

In situ hybridization histochemistry was used to study changes in mRNAs coding neuropeptides such as alpha-calcitonin gene-related peptide (CGRP), beta-CGRP, cholecystokinin (CCK) and galanin, in rat facial motoneurons following axotomy of the facial nerve. In control rats, 38%, 55% and 7% of the facial motoneurons expressed alpha-CGRP, beta-CGRP and CCK mRNAs, respectively. No galanin mRNA-containing motoneurons were observed in these animals. The levels of mRNA for alpha-CGRP, CCK and galanin were increased while the beta-CGRP mRNA level was decreased after axotomy. The levels of mRNAs for these peptides returned to the control values by 2-4 weeks after nerve crush, whereas nerve resection had more prolonged effects. Within 3-4 weeks after injury, nerve resection had greater effects on beta-CGRP, CCK and galanin mRNAs than did nerve crush. Thus, there appear to be differences in the regulation of mRNA expression of these peptides in axotomized motoneurons.

Preproenkephalin gene expression in the rat spinal cord after noxious stimuli

The trans-synaptically activated biosynthesis of the preproenkephalin (PPE) mRNA in the dorsal horn of the rat lumbar spinal cord was examined by an in situ hybridization histochemical technique. As a nociceptive stimulus, a small amount of formalin was injected into the right hindpaw, and quantitative and qualitative changes of PPE-mRNA expression were determined by emulsion autoradiography. Formalin injection was found to result in a significant increase in the number and signal intensity of neurons expressing PPE-mRNAs in the superficial and deep layers of the ipsilateral spinal dorsal horn. Expression of PPE-mRNA increased within 1 h after formalin injection in neurons of deep layers, but gradually for at least 24 h in neurons in the superficial layers. These results at the level of the spinal cord showed that differential responses of PPE neurons related to the pain sensation occurred trans-synaptically after nociceptive stimulation applied to the periphery.

Co-expression of α-CGRP and β-CGRP mRNAs in the rat dorsal root ganglion cells

Abstract We examined the expression of α-calcitonin gene-related peptide (α-CGRP) and β-CGRP mRNAs in the rat dorsal root ganglion (DRG) using in situ hybridization histochemistry with oligonucleotide probes. Analysis of autoradiograms showed that α-CGRP mRNA labeled 36.4% of all DRG neurons and β-CGRP mRNA labeled 30.8%. Small and medium-sized neurons expressed both types of mRNA, but large neurons showed a predominance of α-CGRP mRNA expression. The colocalization of α-CGRP and β-CGRP mRNAs was shown at a cellular level in consecutive DRG sections. Thus, we demonstrated that α-CGRP and β-CGRP were distributed differently in the DRG neurons, although genes coding for these neuropeptides coexist in the small or medium-sized neurons.

In situ hybridization analysis of the somatostatin-containing neuron system in developing cerebellum of rats

We used in situ hybridization histochemistry to examine the postnatal development of the somatostatin (SRIF) synthesizing system in the cerebellum of rats. There are numerous hybridizing neurons from 1 to 9 days after birth. These occur throughout the cerebellum including the developing medulla and cortex except in the external granular cell layer. The lateral cerebellar nucleus also contains SRIF gene-containing cells. The intensity of the signals for SRIF mRNA in the cerebellum decreases with age. There is a drastic decrease in SRIF mRNA in the lateral cerebellar nucleus. SRIF cells cannot be detected in the lateral cerebellar nucleus of adult rats, whereas a small, yet significant number of SRIF cells are scattered in the cerebellar medulla. However, the cerebellum of adult rats still contains a significant number of labeled cells in the granular cell layer, although the intensity for SRIF mRNA decreases from 14 days after birth to adulthood. SRIF gene-expressing cells in the cerebellar cortex are located primarily in the granular cell layer and appear to correspond to Golgi cells judging from their characteristic features. These results are consistent with our previous immunohistochemical study on the decrease of SRIF immunoreactivity in the cerebellum of adult rats. These findings, together with a recent study of transient SRIF receptor-expressing cells in the developing cerebellum suggest that SRIF acts during cerebellar development.

Different ontogenetic profiles of cells expressing prepro-neurotensin/neuromedin N mRNA in the rat posterior cingulate cortex and the hippocampal formation

The ontogeny of the expression of prepro-neurotensin/neuromedin N messenger RNA (prepro-NT/NN mRNA) in the rat posterior cingulate cortex (retrosplenial cortex) and the hippocampal formation was investigated using in situ hybridization histochemistry. In the primordium of the posterior cingulate cortex and the hippocampal formation, prepro-NT/NN mRNA was first expressed on embryonic day 17, and was found in the subiculum, layers II-III in areas 29a and 29b, and layer VI in the posterior cingulate cortex at birth. Expression was also observed in the CA1 field. In the adult rat, the expression of prepro-NT/NN mRNA was reduced in the posterior cingulate cortex, and only a few positive cells were seen here. However, the CA1 field and the subiculum still contained numerous positive cells.