• The Korean Journal of Physiology
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• v.28 no.2
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• pp.123-132
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• 1994

The present study was undertaken to elucidate the desensitization of cutaneous receptors and the conduction block of the afferent nerves induced by direct application of allyl isotheocyanate (mustard oil) to the receptive field (RF) or onto the afferent nerve, respectively. Dorsal horn cell responses to mechanical stimulations of RF were completely suppressed when mustard oil was applied to either the afferent nerve or the whole area of RF. C-fiber responses of dorsal horn cells were more susceptive to mustard oil than A-fiber activities. This was confirmed by the experiment in which the compound action potentials recorded from rat tibial nerve before and after topical application of mustard oil were compared. The higher the concentration of mustard oil and the longer the application time, the more powerful desensitization or conduction block was induced. From the results of the present study, it is suggested that the desensitization of the afferent fiber and sensory receptors induced by mustard oil results mainly from the conduction block of C-fiber in the primary afferent nerve.

• Journal of Yeungnam Medical Science
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• v.33 no.2
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• pp.166-169
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• 2016

Afferent loop obstruction following gastrectomy is a rare but fatal complication. Clinical features of afferent loop obstruction are mainly gastrointestinal symptoms. A 56-year-old female underwent radical total gastrectomy with Roux-en-Y esophagojejunostomy for treatment of advanced gastric cancer. After fourteen months postoperatively, she showed gradual development of edema of both legs. Computed tomography (CT) scan showed disease progression at the jejunojejunostomy site and consequent dilated afferent loop, which resulted in inferior vena cava (IVC) compression. A drainage catheter was placed percutaneously into the afferent loop through the intrahepatic duct and an IVC filter was placed at the suprarenal IVC, and self-expanding metal stents were inserted into bilateral common iliac veins. With these procedures, sympotms related with afferent loop obstruction and deep vein thrombosis were improved dramatically. The follow-up abdominal CT scan was taken 3 weeks later and revealed the completely decompressed afferent loop and improved IVC patency. Surgical treatment should be considered as the first choice for afferent loop obstruction; however, because it is more immediate and less invasive, non-surgical modalities, such as percutaneous catheter drainage or stent placement, can be effective alternatives for inoperable cases or risky patients who have severe medical comorbidities.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.1
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• pp.27-32
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• 2001

We have characterized the aftereffects of impulse activities on the transmission of afferent sensory to the primary somatosensory (SI) cortex of the anesthetized rats (n=22). Following conditioning stimulation (CS, 10 sec, either 5 Hz or 200 Hz) to the receptive field (RF), quantitative determination of the changes of afferent sensory transmission was done by generating post-stimulus time histogram of unit response to the testing stimulation (TS, at 0.5 Hz) to the RF center (RFC) for 60 min. In one group of experiments, CS was delivered to the RF center (RFC). In another group of experiments, CSs were simultaneously given to both RFC and RF outside (RFO, either forepaw or hindpaw). CS of 5 Hz to RFC exerted irreversible facilitation of sensory transmissions evoked by TS. Simultaneous CSs of 5 Hz to RFC and hindpaw RFO exerted reversible suppression of afferent transmission. However, CSs of 5 Hz to RFC and forepaw RFO did not significantly altered afferent sensory transmission to SI cortex neurons. CS of 200 Hz to RFC exerted irreversible suppression of sensory transmissions up to 60 min of experimental period. Simultaneous CSs of 200 Hz to RFC and RFO did not significantly altered afferent sensory transmission to SI cortex neurons. The profiles of CS-induced modulation of afferent sensory transmission were significantly different between two CS conditions. Thus, this study suggests that activity-dependent modulation of afferent transmission from a RF center to the SI cortex may be significantly altered when remote body part was simultaneously activated.

• The Korean Journal of Physiology
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• v.28 no.1
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• pp.105-111
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• 1994

The present study was carried out to determine the effects of intracisternal administration of three doses of bombesin $(0.001,\;0.01\;and\;0.1\;{\mu}g)$ on afferent somatosensory transmission in single neurons of the spinal trigeminal nucleus of anesthetized rats. Lower doses $(0.001\;{\mu}g)$ of bombegin did not change the afferent sensory transmission. Medium doses $(0.01\;{\mu}g)$ of bombesin significantly (p p<0.01) facilitated afferent sensory transmission in the 6 to 30 min post-drug period, but higher doses $(0.1\;{\mu}g)$ inhibited responsiveness of spinal trigeminal neurons in the 16 to 35 min post-drug period. The results indicate that endogenous bombesin-like peptide present in the spinal trigeminal nucleus may participate in the processing of the somatosensory information arising from the face.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.215-219
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• 2007

Small and large conductance $Ca^{2+}$-activated $K^+(SK_{Ca}\;and\;BK_{Ca})$ channels are implicated in the modulation of neuronal excitability. We investigated how changes in peripheral $K_{Ca}$ channel activity affect mechanical sensitivity as well as the afferent fiber type responsible for $K_{Ca}$ channel-induced mechanical sensitivity. Blockade of $SK_{Ca}$ and $BK_{Ca}$ channels induced a sustained decrease of mechanical threshold which was significantly attenuated by topical application of capsaicin onto afferent fiber and intraplantar injection of 1-ethyl-2-benzimidazolinone. NS1619 selectively attenuated the decrease of mechanical threshold induced by charybdotoxin, but not by apamin. Spontaneous flinching and paw thickness were not significantly different after $K_{Ca}$ channel blockade. These results suggest that mechanical sensitivity can be modulated by $K_{Ca}$ channels on capsaicin-sensitive afferent fibers.

• Journal of Acupuncture Research
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• v.20 no.4
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• pp.145-156
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• 2003

Objective : This study is to investigate the effect of electro-acupuncture ST36 on altered transmission of afferent somatosensory information caused by amyloid-${\beta}$(A-${\beta}$) that caused Alzheimer's disease. Methods : The effects of topical application of A-${\beta}$, A-${\beta}$ with ST36, aggregated A-${\beta}$(aA-${\beta}$), aA-${\beta}$ with ST36 and ST36 on the afferent sensory transmission to the neurons in the primary somatosensory(SI) cortex was observed in anesthetized rats. Quantitative determination of the effects of A-${\beta}$, A-${\beta}$ with ST36, aA-${\beta}$, aA-${\beta}$ with ST36 and ST36 was made by generating poststimulus time histogram of evoked response of individual cortical neuron by electrical stimulation of the receptive located in peripheral area(forepaw) Results : The results obtained in present study were summerized as follow : 1. Application of physiological concentrative 0.5 nM A-${\beta}$ caused afferent sensory transmission of SI cortex facilitated. 0.5 nM A-${\beta}$ with ST36 exerted much stronger effects than 0.5 nM A-${\beta}$ alone. 2. Application of $10{\mu}M$ A-${\beta}$ caused afferent sensory transmission of SI cortex unchangeable. But $10{\mu}M$ A-${\beta}$ with ST36 is facilitated at 30 min of post-drug period 3. Application of $10{\mu}M$ aA-${\beta}$ caused afferent sensory transmission of SI cortex diminished. $10{\mu}M$ aA-${\beta}$ with ST36 is diminished after 15min of post-drug period but is facilitated after 75min.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.3
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• pp.129-132
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• 2004

Single unit responses of the ventral posterior medial (VPM) thalamic neurons to stimulation were monitored in anesthetized rats during activation of contralateral primary somatosensory (SI) cortex by GABA antagonist. The temporal changes of afferent sensory transmission were quantitatively analyzed by poststimulus time histogram (PSTH). Mainly, afferent sensory transmission to VPM thalamus was facilitated (15 neurons of total 23) by GABA antagonist (bicuculline) applied to contralateral cortex, while 7 neurons were suppressed. However, when ipsilateral cortex was inactivated by GABA agonist, musimol, there was significant suppression of afferent sensory transmission of VPM thalamus. This suppressed responsiveness by ipsilateral musimol was not affected by bicuculline applied to contralateral cortex. These results suggest that afferent transmission to VPM thalamus may be subjected to the interhemispheric modulation via ipsilateral cortex during inactivation of GABAergic neurons in contralateral SI cortex.

• The Korean Journal of Nuclear Medicine
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• v.22 no.2
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• pp.199-203
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• 1988

The authors observed functional change of the CBD and the afferent loop with the transit time of $^{99m}Tc-DISIDA$ scintigram in patients treated by the surgical operation of gastric ulcers and cancer at Busan National University Hospital from June, 1987 to April, 1988. So authors estimated the time between the peak activity of the CBD and the afferent loop (TCA), the half transit time of the CBD activity (t 1/2 CBD) and the half transit time of the afferent loop activity (t 1/2 A-loop) in 9 patients undergone truncal vagotomy, who have no specific symptoms at 2 to 6 months after the operation, 5 patients undergone the operation without truncal vagotomy, and 7 persons as a control group. The results were as follows: I) In control group, the mean TCA, t 1/2 CBD and t 1/2 duodenum were $8.6{\pm}9.0$ min, $38.7{\pm}17.3$ min. and $28.6{\pm}10.9$ min, respectively. 2) In the operation group without truncal vagotomy, the mean TCA, t 1/2 CBD and t 1/2 A-loop were $10.0{\pm}7.1$ min. $48.2{\pm}22.3$ min. and $39.4{\pm}26.7$ min. respectively. 3) In the operation group with truncal vagotomy, the mean TCA, t 1/2 CBD and t 1/2 A-loop were $15.0{\pm}8.7$ min., $36.1{\pm}16.5$ min. and $42.6{\pm}24.4$ min, respectively. From the above results, we concluded that the transit time of the CBD and the afferent loop is not affected by truncal vagotomy.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.2
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• pp.149-153
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• 2014

Nausea and emesis are a major side effect and obstacle for chemotherapy in cancer patients. Employ of antiemetic drugs help to suppress chemotherapy-induced emesis in some patients but not all patients. Ginger, an herbal medicine, has been traditionally used to treat various kinds of diseases including gastrointestinal symptoms. Ginger is effective in alleviating nausea and emesis, particularly, for cytotoxic chemotherapy drug-induced emesis. Ginger-mediated antiemetic effect has been attributed to its pungent constituents-mediated inhibition of serotonin (5-HT) receptor activity but its cellular mechanism of action is still unclear. Emetogenic chemotherapy drugs increase 5-HT concentration and activate visceral vagal afferent nerve activity. Thus, 5-HT mediated vagal afferent activation is essential to provoke emesis during chemotherapy. In this experiment, water extract of ginger and its three major pungent constituent's effect on 5-HT-evoked responses were tested on acutely dispersed visceral afferent neurons with patch-clamp methods. The ginger extract has similar effects to antiemetic drug ondansetron by blocking 5-HT-evoked responses. Pungent constituents of the ginger, [6]-shogaol, [6]-gingerol, and zingerone inhibited 5-HT responses in a dose dependent manner. The order of inhibitory potency for these compounds were [6]-shogaol>[6]-gingerol>zingerone. Unlike well-known competitive 5-HT3 receptor antagonist ondansetron, all tested ginger constituents acted as non-competitive antagonist. Our results imply that ginger and its pungent constituents exert antiemetic effects by blocking 5-HT-induced emetic signal transmission in vagal afferent neurons.

• The Korean Journal of Physiology
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• v.22 no.2
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• pp.231-243
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• 1988

This study was performed to investigate the mechanism of changes in arterial blood pressure, as a typical example of somatosympathetic reflex, induced by activation of muscular afferent nerves. Cats were anesthetized with ${\alpha}-chloraloae$ (60 mg/kg, i.p.). Afferent fibers in muscle nerve were activated by various method muscle contraction, electrical stimulation of muscle nerves, intraarterial injection of some algesic substances and noxious mechanical stimulation etc-and the evoked changes in arterial blood pressure were monitored. The effects of intravenous or direct spinal administration of morphine on the changes in arterial blood pressure induced by activation of the muscle afferent fibers were observed and also the effects of spinal lesions made in the $L1{\sim}L3$ spinal cord on them were studied to identify the ascending spinal pathways of the somatosympathetic reflexes. Followings are the results obtained. 1) The stimulation of medial gastrocnemius nerve under non-paralyzed condition with C-strength, low frequency (lower than 20 Hz) stimuli elicited a depressor response and a pressor response was elicited with C-strength, high frequency stimuli, of which the maximal response was observed at 100 Hz stimulation. 2) When the animal was paralyzed, depressor response to stimulation of the medial gastrocnemius nerve was observed with C-strength, $0.5{\sim}5Hz$ stimuli although the amplitude of the depressor response was decreased. The maximal pressor response was observed during stimulation with C-strength, $20{\sim}100Hz$ stimuli. 3) Intraarterial injection of some algesic substances induced marked pressor responses while noxious mechanical stimulation of the medial gastrocnemius muscle was not enough to elicit any significant changes (larger than 10 mmHg) in arterial blood pressure. 4) Systemically administered morphine (2 mg/kg) lowered the arterial blood pressure immediately and persistently and it was reversed by administration of naloxone. Direct spinally administered morphine did not elicit any changes. 5) The pressor response elicited by the activation of muscle afferent nerves was strengthened by systemic morphine administration while the depressor response tended to decrease. 6) Morphine administered on the spinal cord directly, decreased pressor response but did not change depressor response. From the above results it is concluded that there are separate groups of afferent nerves in the medial gastrocnemius nerve, which elicit pressor and depressor responses and the spinal ascending pathways of them are also separated from each other.