• The Korean Journal of Physiology
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• 제27권1호
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• pp.79-91
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• 1993

The present study was carried out to determine the effects of cocaine (0.25, 1.0, 10.0 mg/kg, i.p.) on the interactions between spontaneously active neurons within ensembles of simultaneously recorded neurons in the primary somatosensory cortex (Sl, n= 20) and the ventroposterolateral (VPL, n= 16) thalamic nucleus of awake rats. Spike triggered cross correlation histograms were constructed between pairs of simultaneously recorded neurons. Among 101 neuronal pairs analyzed, 22.7% showed correlations indicative of various functional connections among the cortical cells, two corticothalamic interactions and one thalamocortical excitatory interaction. There were also 15 cofiring activities among SI cortical cells. These functional connectivities appeared to be modulated (weakened, abolished, or strengthened) during the 5 to 30 min following cocaine injection. The effects of saline were tested as a control, but it did not appear to alter the functional connectivities. In general, cocaine-induced changes of the functional interactions were mainly due to the concomitant alterations of the uncorrelated background discharges. These results suggest that the biphasic effects of cocaine on the spontaneously established neural networks among the SI cortical and the VPL thalamic cells of conscious rat were mainly indirect. However, various changes of the functional interactions by different doses of cocaine appeared to be a possible neural network mechanism for the cocaine induced modulation of afferent somatosensory transmission.

• The Korean Journal of Physiology
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• 제22권2호
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• pp.179-187
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• 1988

This study was conducted to investigate the effects of epinephrine and norepinephrine on basal gastric acid secretion and plasma gastrin and secretin concentration in the conscious rat. One hundred and eighty-four albino rats with gastric cannula were used after 18 hours or more of fast, with water ad libitum. In a restraint cage for collection of gastric juice, physiological saline (0.9% NaCl) was continuously infused into the jugular vein through a catheter for one hour at a rate of 1 ml/hr (control period). Immediately after the control period, epinephrine (1, 2, 4, 8 and $16{\mu}g/ml/hr)$, norepinephrine (1, 2, 4, 8 and $16{\mu}g/ml/hr)$ or physiological saline (1 ml/hr) was infused for another one hour. Gastric juice was collected at one hour interval for two hours infusion period. Adrenergic antagonists, phentolamine and propranolol were injected into the jugular vein 5 min prior to the infusion of epinephrine or norepinephrine at a dose of 0.2 mg/0.1 ml. Blood was sampled from the jugular vein for the radioimmunoassay of plasma gastrin and secretin after the collection of gastric juice. The results were as follows: 1) Both epinephrine and norephinephrine significantly increased gastric acid output in a dosedependent manner. 2) The effects of epinephrine and norepinephrine on the gastric acid secretion were antagonized by the pretreatment with phentolamine and propranolol. 3) Plasma gastrin and secretin concentrations were not significantly affected by the intravenous infusion of epinephrine and norepinephrine. It can be inferred from the above results that epinephrine and norepinephrine facilitate gastric acid secretion in conscious rats and the mechanism of which is attributed to ${\alpha}\;and\;{\beta}$ adrenergic receptors rather than gastrin and secretin.

• Journal of Ginseng Research
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• 제23권2호
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• pp.81-87
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• 1999

신성고혈압백서모델인 one-kidney, one-clip Goldblatt 고혈압백서에서 혈압과 NO생성에 미치는 고려홍삼 사포닌과 비사포닌의 영향을 규명하고자, 무마취 무제한상태에서 혈압을 측정하고, 혈중 NO와 NO합성효노에 대한 활성 및 단백량을 실시한 결과이다. 고려홍삼 사포닌은 정상혈압백서 및 신성고혈압백서에서 모두 혈압을 강하시키는 효과가 현저하였는데 혈압강하는 초기 2-4분 동안 최대를 보였으며 혈압강하와 동시에 심박수의 증가 현상이 관찰되었다. 그러나 고려홍삼 비사포닌은 혈압강하효과와 심박수의 증가현상은 사포닌에 비하여 미미 하였다. 고려홍삼 사포닌에 의한 혈압강하 현상과 NO와의 상관관계를 규명하기 위하여 혈중 NO를 측정한 결과 홍삼사포닌은 혈중 NO를 상승시켰다. NO합성효소의 활성도를 측정하기 위하여 $[^{3}H]-L-arginine$의 $[^{3}H]-L-cioulline$으로의 변환률을 측정한 결과 고려홍삼 사포닌에 의하여 NO합성효소의 활성도는 증가하였다. 이상의 결과를 종합해 볼 때 고려홍삼은 혈압을 강하시키는 효과가 있으며, 이러한 혈압강하는 주로 사포닌 성분에 의한 것으로 생각된다. 이러한 고려홍삼 혈압강하 현상은 혈중의 NO량을 증가시키는 것에 기인하며 NO의 증가는 NO합성효소의 활성도의 증가에 기인하는것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제3권6호
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• pp.555-563
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• 1999

It is well known that stress induces analgesia. This study was designed to demonstrate the stress-induced analgesia by employing hemorrhage and restraint and to investigate its mechanism and sex difference. The degree of pain was assessed by measuring the magnitude of jaw opening reflex produced by a noxious electrical stimulation in the dental pulp and by measuring the latency to withdraw the tail from a heat ray. Restraint showed an antinociceptive response. A significant increase in pain threshold on bleeding was shown and the increase was larger in male group than in female group. The tail flick latency (TFL) on bleeding after AVP antagonist injection into the ventricle was decreased and the decrease was greater in male rats than in female rats. Castration resulted in a significant reduction of TFL. This effect was reversed by treatment with sex hormones. TFL was decreased during hemorrhage in castrated rats. This response was opposite to that in non-castrated rats. TFL was further decreased during hemorrhage after infusion of AVP antagonist, and there was a significant sex difference. These results suggest that both restraint and hemorrhage produce an antinociception and that, in hemorrhage-induced analgesia, AVP and sex hormones may play an important role and male rats show a greater analgesic response.

• Biomolecules & Therapeutics
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• 제5권3호
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• pp.292-298
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• 1997

General pharmacological properties of ι-muscone, the major component of musk, were investigatedin mice, rats and guinea pig. The administration of ι-muscone (1, 10, 100 mg/kg, p.o.) in mice had no effects in general behaviors, and no influences on analgesic actions and normal body temperature. Muscle relaxant action, intestinal propulsion and gastric secretion were not observed even at the high dose of 100 mg/kg. ι-Muscone (1, 10, 100 mg/kg, p.o.) given to conscious rats showed no effect on mean blood pressure and heart rate. It showed no direct effect at 2.4$\times$10.3 mg/ml and 2.4$\times$10-2 mg/ml in isolated uterus of rats and ileum of guinea pig, and also had no inhibition of contraction induced by oxytocin and histamine.

• The Korean Journal of Physiology
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• 제23권1호
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• pp.119-127
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• 1989

This study was undertaken to investigate the effect of medial amygdala on the gastric acid secretion and plasma gastrin concentration in the rats with chronic gastric fistula. After the medial nucleus of amygdala was damaged bilaterally by radiofrequency a. c. through stereotaxically inserted electrodes, the gastric juice was collected in the basal and histamine-stimulated states for 1 hour. The gastric juice was also collected while the medial nucleus of amygdala was stimulated with biphasic square wave in the both states. After the collection of the gastric juice, blood samples were drawn from the abdominal aorta for the radioimmunoassay of plasma gastrin. The results were as follows: 1) The damage of the medial amygdala significantly decreased the gastric juice volume and the acid output in the histamine-stimulated state. 2) The electrical stimulation of the medial amygdala significantly increased the gastric juice volume and the acid output in the histamine-stimulated state, and the acid output in the basal state. 3) The damage of the medial amygdala significantly decreased the plasma gastrin concentration but the electrical stimulation of the medial amygdala did not affect the plasma gastrin concentration. It is therefore suggested that the medial amygdala has a facilitatory influence on the histamine-stimulated gastric acid secretion in rats, and the influence may not be attributed to gastrin release.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3473-3479
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• 2009

비펩타이드성 안지오텐신 수용체 길항제로 새롭게 개발된 KR-31081에 대한 생체 내 활성을 세가지 동물모델에서 검증하였다. 척수장애 동물모델에서 KR-31081은 로사탄보다 40배 이상의 경쟁적인 혈압강하 효과를 나타내었으며, 신성고혈압쥐 모델에서 KR-31081은 로사탄보다 10배 가량의 지속형 효과를 나타내었다. 또한 개실험에서 구강 투여한 KR-31081은 로사탄보다 20배 이상의 지속적인 혈압강하 효과를 나타내었다. 실험에 사용된 동물 모델 시스템에서 다른 혈관조절물질들과 상호작용을 하지 않는 것으로 나타난 KR-31081은 향후 고혈압 및 혈관질환에 대한 연구 및 진단에 활용될 수 있을 것이라고 판단된다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권3호
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• pp.345-351
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• 1998

The role of nitric oxide (NO) in the hemorrhagic hypotension was examined using a NO synthase inhibitor, $N^{\omega}-nitro-L-arginine$ methyl ester (L-NAME), in conscious rats. The rats were bled at a constant rate (2 ml/kg/min) through a femoral arterial catheter until the mean arterial pressure (MAP) was reduced by 50 mmHg. We studied the responses to hemorrhage under normal condition (Control) and after the pretreatment with 3 doses of L-NAME (1.6, 8, 40 mg/kg i.v. of NOX1.6, NOX8, and NOX40, respectively). Intravenous bolus injection of L-NAME produced a sustained increase in MAP and decrease in heart rate (HR). During hemorrhage, the MAP fell faster in the NOX8 and NOX40-treated groups than in Control group, but the control group showed same response to NOX1.6. HR greatly increased in NOX groups. The recovery from hemorrhagic hypotension was slowed in the control group, which was not treated with L-NAME. In comparison with the control group, NOX8 and NOX1.6-treated groups registered a significant recovery in MAP during the 15 min recovery period, but NOX40 brought about only a slight increase in MAP. NO precursor, L-arginine (150 mg/kg i.v.), produced significant bradycardic responses before and after hemorrhage and significant depressor response only after hemorrhagic hypotension regardless of pretreatment with L-NAME. These data suggest that the role of NO in blood pressure regulation is greater after hemorrhagic hypotension than basal condition, but the effect of NO can be detrimental to the recovery from hemorrhagic hypotension. In addition, the bradycardic response of L-arginine provides indirect evidence that NO may inhibit sympathetic activity, especially after hemorrhagic hypotension.

• Biomolecules & Therapeutics
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• 제11권1호
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• pp.51-57
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• 2003

General pharmacological properties of ADP, a new pharmaceutical composition, which contains a mixed water extract obtained from the mixture of Phellodendron cortex (Phellodendron amurense) and Anemarrhena rhizoma (Anemarrhena asphodeloides), as the active ingredients, were investigated in experimental animals administering orally and in vitro test system. ADP had no influences on general behavior, pentobarbital sleeping time, spontaneous motor activity, motor coordination of mice, normal body temperature, chemoshock produced by pentylenetetrazole and writhing syndromes induced by 0.8% acetic acid at the dose of 150 and 1500 mg/kg. Gastric secretion of rats and intestinal motility of mice were not also influenced by the administration of ADP at doses of 150 and 1500 mg/kg, with the exception of the significant decrease of free HCI concentration at a dose of 1500 mg/kg in rats. ADP (150 and 1500 mg/kg) did not alter mean arterial blood pressure and heart rate in conscious rats. ADP given to anesthetized rats showed no effect on respiratory rate at the same doses. In in vitro experiments, ADP at the concentration of 150 mg/L did not show direct effect and inhibitory or augmentative action on histamine- or acetylcholine-induced contractions in the isolated ileum of guinea-pig. Taken together, these results indicate that ADP does not induce any adverse effects in experimental animals.

• 대한한방내과학회지
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• 제29권1호
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• pp.189-199
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• 2008

Background & Objective : Jichul-hwan(JCH) has been used for the treatment of functional dyspepsia, regarded as a gastric dysmotility disease. We investigated the effects of JCH on gastric motility and its mechanisms of action in rats. Methods : The gastric wall was injured by tracting a part of stomach body in rats. Gastric emptying was measured after administration of normal saline(NS) or JCH in normal rats and gastric wall injured rats. To evaluate the mechanism of JCH under delayed gastric emptying conditions, normal rats were treated with atropine sulfate(1mg/kg, s.c.), quinpirole HCl(0.3mg/kgg, i.p.), $NAME(N^{G}-nitro-L-arginine$ methyl ester, 75mg/kg s.c.) and cisplatin(10mg/kg, i.p.). The gastric slow waves were measured for 30 minutes before and after administration of each solution(NS, JCH). Results : JCH 110.1mg/kg improved gastric emptying for 2 hrs(p=0.014). JCH 110.1mg/kg improved gastric emptying in the gastric wall injured rats(p=0.001). Under the delayed gastric emptying, JCH 110.1mg/kg improved gastric emptying in the group treated with atropine $sulfate(1.83{\pm}0.96$ vs $8.43{\pm}8.46$, p=0.003), but aggravated it with quinpirole $HCl(4.7{\pm}2.9$ vs $1.61{\pm}2.09$, p=0.021). Administration JCH 110.1mg/kg increased EGG power in rats. Conclusions : JCH stimulates gastric motility through the cholinergic pathway, so we expect that it would be effective in the treatment of dysmotility-like functional dyspepsia with low activity of vagus nerve.