• YAKHAK HOEJI
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• v.43 no.4
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• pp.411-418
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• 1999

Intracerebroventricular (ICV) infusion of morphine (MOR) produces strong analgesia in man and animals. The analgesic effect is thought to be mediated by the centrifugal inhibitory control. But neural mechanisms of the analgesic effect of ICV morphine are not well understood. In the present study, we found that ICV MOR had dual actions on the activity of dorsal horn heurons: it produced both inhibition and excitation of dorsal horn neurons. Since MOR exerts its action via three different types of opioid receptors, we further sought to investigate if there are differential effects of opioid receptor agonists on dorsal horn neurons when administered intracerebroventricularly. Effects of ICV MOR were tested in 28 dorsal horn neurons of the spinal cord in the cat. ICV MOR inhibited, excited and did not affect the heat responses of dorsal horn neurons. ICV DAMGO and DADLE, $\mu$- and $\delta$-opioid agonist, respectively, exhibited the excitation of dorsal horn neurons. In contract, U-50488, a k-opioid agonist, exhibited both the inhibition and excitation of dorsal horn neurons. These results suggest that opioid receptors have different actions on activity of dorsal horn neuron and that the inhibitory action of k-opioid agonist may subserve the analgesia often produced by ICV MOR.

• Journal of Species Research
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• v.12 no.3
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• pp.203-211
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• 2023

Five ciliate species of Euplotes were isolated from fresh and coastal water during a sampling survey to identify unrecorded ciliates in South Korea. Their morphology was investigated using live observation, protargol and "wet" silver nitrate staining methods. Brief descriptions and microphotographs of each species and a comparison with related species are provided. Euplotes focardii is characterized by an average size of 65×47 ㎛ after protargol impregnation, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-eurystomus type. Euplotes nobilii shows an average size of 34×20 ㎛ after protargol staining, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type. Euplotes octocarinatus, the only freshwater species described in the present study, is characterized by an average size of 66×46 ㎛ after protargol impregnation, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type. Euplotes petzi has an average size of 43×30 ㎛ after protargol staining, a macronucleus hook-shaped and dorsal argyrome pattern in double-patella type. Euplotes raikovi is characterized by an average size of 40×24 ㎛ after protargol staining, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type.

• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.877-885
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• 2000

Objective : The NOS inhibitors exhibit antinociceptive activity in rat model of neuropathic pain. NOS activity increases in the dorsal root ganglia(DRG) in neurop-athic pain. However, NOS activity decreases in the dorsal horn of spinal cord in the nerve injury models of neuropathic pain. To investigate whether the mechanism of decrease of NOS expression in the dorsal horn is related to a secondary effect resulting from increased NO production and likewise in the spinal DRG in the spinal nerve ligation model of neuropathic pain. Methods : We conducted behavioral tests for neuropathic pain, and nNOS immunohistochemistry and NADPH-diaphorase histochemistry after tight ligation of the 5th lumbar(L5) and 6th lumbar(L6) spinal nerves and L5 dorsal rhizotomy. Results : Typical neuropathic pain behaviors occurred 7 days after post-ligation in the neuropathic surgery group, but neuropathic pain behaviors in the dorsal rhizotomy group were absent or weak 7 days after post-operation. There was a decrease in the number of nNOS immunoreactive dorsal horn neurons on the both side(especially ipsilateral side) 7 days after post-ligation. The number of nNOS immunoreactive neurons in both side of the dorsal horn was not decreased 7 days after L5 dorsal rhizotomy. Conclusion : These data indicate that the changes in the injured DRG is essential for development and maintenance of neuropathic pain, and mechanism of decrease of nNOS expression in the dorsal horn is a secondary effect against the changes in the DRG including increased NO production in the spinal nerve ligation model of neuropathic pain.

• 대한약리학회:학술대회논문집
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• 2006.10a
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• pp.84.1-84.1
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• 2006

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.303-303
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• 1994

ICV infusion of morphine (MOR) produces strong analgesia in man and animals. The analgesic effect is thought to be mediated by the centrifugal inhibtory control, But neural mechanisms of the analgesic effect of ICV morphine are not well understood. For example, in the previous studies, ICV morphine does not inhibit nociceptive transmission in the spinal cord. On the contrary, ICV MOR often excites activity of dorsal horn neuron in the spinal cord. In the present study, we found that ICV MOR had dust actions on activity of dorsal horn neuron that it produced both inhibition and excitation of dorsal horn neurons. Since MOR exerts i Is action via three different types of opioid receptors, we further sought to investigate if there are differential effects of opioid receptor agonists on dorsal horn neurons when administered ICV.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.28-34
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• 1990

The ipsilateral dorsal lobe of the brain one or two days after cutting a left antenna in Pieris rapae has been examined with electron microscope to investigate the connection of the receptor cells between antenna and dorsal lobe. The proximal removal of the left antenna leads to the weakly-dark, semidark or dark degeneration of antennal receptor tenninals in ipsilateral dorsal lobe. Therefore, it is concluded that some of antennal receptor cells which project into the brain terminate in ipsilateral dorsal lobe located immediately behind the antennal lobe.

• The Korean Journal of Pain
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• v.19 no.1
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• pp.22-32
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• 2006

Background: This study was conducted to investigate the roles of the spinal and peripheral ${\gamma}$-aminobutyric acid (GABA)- ergic systems for the mechanical hypersensitivity produced by chronic compression of the dorsal root ganglion (CCD). Methods: CCD was performed at the left 5th lumbar dorsal root ganglion. The paw withdrawal threshold (PWT) to von Frey stimuli was measured. The mechanical responsiveness of the lumbar dorsal horn neurons was examined. GABAergic drugs were delivered with intrathecal (i.t.) or intraplantar (i.pl.) injection or by topical application onto the spinal cord. Results: CCD produced mechanical hypersensitivity, which was evidenced by the decrease of the PWT, and it lasting for 10 weeks. For the rats showing mechanical hypersensitivity, the mechanical responsiveness of the lumbar dorsal horn neurons was enhanced. A similar increase was observed with the normal lumbar dorsal horn neurons when the GABA-A receptor antagonist bicuculline was topically applied. An i.t. injection of GABA-A or GABA-B receptor agonist, muscimol or baclofen, alleviated the CCD-induced hypersensitivity. Topical application of same drugs attenuated the CCD-induced enhanced mechanical responsiveness of the lumbar dorsal horn neurons. CCD-induced hypersensitivity was also improved by low-dose muscimol applied (i.pl.) into the affected hind paw, whereas no effects could be observed with high-dose muscimol or baclofen. Conclusions: The results suggest that the neuropathic pain associated with compression of the dorsal root ganglion is caused by hyperexcitability of the dorsal horn neurons due to a loss of spinal GABAergic inhibition. Peripheral application of low-dose GABA-A receptor agonist can be useful to treat this pain.

• Annals of Clinical Neurophysiology
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• v.7 no.2
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• pp.97-100
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• 2005

Background: The most distal sensory fibers of the feet are often affected first in polyneuropathy. However, they are not evaluated in routine nerve conduction studies. Thus we evaluated the dorsal sural sensory nerve in patients with sensorimotor polyneuropathy with normal sural response, in order to assess the usefulness in electrodiagnostic practice. Methods: In this study, 53 healthy subjects and 27 patients with clinical evidence of sensorimotor polyneuropathy were included. In all subjects, peripheral motor and sensory nerve studies were performed on the upper and lower limbs including dorsal sural nerve conduction studies. On electrodiagnostic testing, all patients had normal sural responses. Results: The dorsal sural sensory nerve action potentials (SNAPs) mean amplitude was $13.12{\pm}5.68{\mu}V$, mean latency was $3.12{\pm}0.43msec$, and mean sensory conduction velocity (SCV) was $36.50{\pm}3.40m/s$ in healthy subjects. In 7 of 27 patients, the dorsal sural nerve SNAPs were absent bilaterally, and in 20 patients, the mean dorsal sural nerve distal latency was longer($3.40{\pm}0.48ms$, P=0.006), and mean SCV was slower than in healthy subjects($35.08{\pm}4.59$, P=0.043). However, dorsal sural nerve amplitude was not different between the groups (P=0.072). Conclusions: Our findings suggest that dorsal sural nerve conduction studies should be included in the routine electrodiagnostic evaluation of patients with suspected polyneuropathy and normal sural nerve responses.

• Molecules and Cells
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• v.38 no.11
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• pp.1007-1012
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• 2015

EphA7 is a key molecule in regulating the development of the dien- and mesencephalon. To get insight into the mechanism of how EphA7 gene expression is regulated during the dorsal specification of the dien- and mesencephalon, we investigated the cis-acting regulatory sequence driving EphA7 to the dorsal midline of the dien- and mesencephalon. Transgenic LacZ reporter analysis, using overlapping EphA7 BACs, was used to narrow down the dorsal midline-specific enhancer, revealing the 25.3 kb genomic region as the enhancer candidate. Strikingly, this genomic DNA was located far downstream of the EphA7 transcription start site, +302.6 kb to +327.9 kb. Further enhancer mapping, using comparative genomic analysis and transgenic methods, showed that the 187 bp genomic DNA alone, approximately 305 kb downstream of the EphA7 transcription start site, was sufficient to act as the dorsal midline-specific enhancer of EphA7. Importantly, our results indicate that the 187 bp dorsal midline-specific enhancer is critically regulated by homeobox transcription factors during the development of the dien- and mesencephalon.

• ALGAE
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• v.22 no.4
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• pp.325-331
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• 2007

Cryptoglena pigra Ehrenberg from Korea was a photosynthetic euglenoid alga, which had typical characteristics of the Euglenales. The ultrastructure examination of C. pigra revealed certain features which were distinctly photosynthetic euglenoid: one U-shaped chloroplast with thylakoid membranes; two paramylon grains appressed to both sides of the chloroplast; eyespot associated with the chloroplast but not part of it. Three flagellar roots were associated with the two basal bodies. The four-membered dorsal root arose from the dorsal body and extended anteriorly following the reservoir membrane. At the base of the reservoir the dorsal band was nucleated by the dorsal root and it ran anteriorly between the reservoir membrane and eyespot. The dorsal band was continued with the microtubules of the canal and the pellicle. The singlet dorsal microtubules at the transition level arranged into doublets by a successive linkage of the existing adjacent microtubules, and the doublets rearranged into the cytoskeletal microtubules that were continuous with four microtubules in pellicles. Finally, the sixteen ridges gave rise to the pellicular ridges. The five to six-membered ventral root extended anteriorly into a cytoplasmic pocket through the reservoir and lined a cytoplasmic pocket.