• The Korean Journal of Physiology
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• 제28권2호
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• pp.197-202
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• 1994

The present study was aimed to determine if endogenous L-arginine-nitric oxide (NO) pathway has central, rather than peripheral, mechanisms in blood pressure regulation. Arterial blood pressure and heart rate responses to acute inhibition of the t-arginine-NO pathway were examined in rats anesthetized with thiopental (50 mg/kg, IP). An intracerebroventricular (ICV) cannula was placed in the left lateral ventricle. The right femoral artery was cannulated to measure arterial blood pressure and the vein to serve as an infusion route. $N^G-nitro-L-arginine$ methyl ester (L-NAME) was infused either intracerebroventricularly or intravenously. ICV infusion $(1.25\;{\mu}L/min)$ of L-NAME $(20\;or\;100\;{\mu}g/kg)$ per minute for 60 min) increased the mean arterial pressure and heart rate. Plasma renin concentrations(PRC) were significantly lower in L-NAME-infused group than in the control. L-Arginine $(60\;{\mu}g/min,\;ICV)$ prevented the pressor response to ICV L-NAME. The pressor response was not affected by simultaneous intravenous infusion of saralasin, but was abolished by hexamethonium treatment. Intravenous infusion $(40\;{\mu}L/min,\;10{\sim}100\;{\mu}g/kg\;per\;minute\;for\;60\;min)$ also increased blood pressure, while it decreased heart rate. These results indicate that endogenous L-arginine-NO pathway has separate central and peripheral mechanisms in regulating the cardiovascular function. The central effect may not be mediated via activation of renin-angiotensin system, but via, at least in part, activation of the sympathetic outflow.

• Biomolecules & Therapeutics
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• 제11권2호
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• pp.119-125
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• 2003

The present study was conducted to investigate the effects of bornyl acetate on arterial blood pressure and vascular contractile responses in the normotensive rats and to establish the mechanism of action. Both phenylephrine (an adrenergi$\alpha$-receptor agonist) and high potassium (a membrane-depolarizing agent) caused greatly contractile responses in the isolated aortic strips. These phenylephrine (10$^{-5}$ M)-induced contractile responses were depressed in the presence of high concentrations of bornyl acetate (10∼20 $\mu\textrm{g}$/ml), but not affected in low concentrations of bornyl acetate (2.5∼5$\mu\textrm{g}$/ml). High potassium (5.6 ${\times}$ 10$^{-2}$ M)-induced contractile responses were also greatly inhibited in the presence of bornyl acetate (2.5∼20 $\mu\textrm{g}$/ml) in a dose-dependent fashion. Bornyl acetate (1∼10 mg/kg) given into a femoral vein of the normotensive rat produced a dose-dependent depressor response, which is transient (data not shown). Interestingly, the infusion of a moderate dose of bornyl acetate (3mg/kg/30 min) made a significant reduction in pressor responses induced by intravenous norepinephrine. Collectively, these results obtained from the present study demonstrate that intravenous bornyl acetate causes a dose-dependent depressor action in the anesthetized rat at least partly through the blockade of adrenergic $\alpha$$_1$-receptors. bornyl acetate also causes vascular relaxation in the isolated aortic strips of the rat via the blockade of adrenergic $\alpha$$_1$-receptors, in addition to the unknown mechanism of direct vasorelaxation.

• Journal of Chest Surgery
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• 제32권11호
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• pp.984-988
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• 1999

Background: Donor-specific blood transfusion(DSBT) before organ transplantation has been demonstrated to prolong allograft survival; the mechanism of this effect has remained unclear. Only a few researches have been performed on this subject in our country. Material and Method: To investigate the effect of DSBT, we selected 5 donor recipient combinations using rats of pure strain such as PVG, ACI, and LEW. One ml of donor whole blood was transfused to each recipient through the femoral vein 7 days prior to transplantation. The donor heart was transplanted to the recipient's abdominal vessels heterotopically using modified Ono and Lindsey's microsurgical technique. Five transplantations were done for each combination. Postoperatively, donor heart beat was palpated everyday through the recipent's abdominal wall. Rejection was defined as complete cessation of donor heart beat. Result: The allogeneic heart grafts transplanted from PVG strain to ACI strain(PVG ACI) without DSBT were acutely rejected(mean survival 10.2 days). With pretransplant DSBT, the cardiac allografts in PVG ACI and LEW PVG combinations survived indefinitely(more than 100 days), those in ACI PVG combination survived 12 to 66 days(mean 31.8 days), those in PVG LEW survived 8 to 11 days(mean 10.0 days), and those in ACI LEW survived 7 to 9 days(mean 8.0 days). In brief, DSBT prior to heart transplantation was definitely effective in PVG ACI and LEW PVG combinations and moderately effective in ACI PVG combination, but not effective in PVG LEW and ACI LEW combinations. Conclusion: DSBT prior to heart transplantation showed variable effects, but might prolong cardiac allograft survival indefinitely in some donor recipient strain combinations. The mechanism of this effect should be further investigated.

• Archives of Pharmacal Research
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• 제26권3호
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• pp.214-223
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• 2003

The present study was conducted to investigate the effects of green tea extract (GTE) on arterial blood pressure and contractile responses of isolated aortic strips of the normotensive rats and to establish the mechanism of action. The phenylephrine ($10^{-6}~10^{-5}M$)-induced contractile responses were greatly inhibited in the presence of GTE (0.3~1.2 mg/mL) in a dose-dependent fashion. Also, high potassium ($3.5{\times}10^{-2}~5.6{\times}10^{-2}{\;}M$)-induced contractile responses were depressed in the presence of 0.6~1.2 mg/mL of GTE, but not affected in low concentration of GTE (0.3 mg/mL). However, epigallocatechin gallate (EGCG, $4~12{\;}{\mu}g/mL$) did not affect the contractile responses evoked by phenylephrine and high $K^+$. GTE (5~20 mg/kg) given into a femoral vein of the normotensive rat produced a dose-dependent depressor response, which is transient. Interestingly, the infusion of a moderate dose of GTE (10 mg/kg/30 min) made a significant reduction in pressor responses induced by intravenous norepinephrine. However, EGCG (1 mg/kg/30 min) did not affect them. Collectively, these results obtained from the present study demonstrate that intravenous GTE causes a dose-dependent depressor action in the anesthetized rat at least partly through the blockade of adrenergic $\alpha_1$-receptors. GTE also causes the relaxation in the isolated aortic strips of the rat via the blockade of adrenergic $\alpha_1$-receptors, in addition to the unknown direct mechanism. It seems that there is a big difference in the vascular effect between GTE and EGCG.

• International Journal of Oral Biology
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• 제33권3호
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• pp.97-103
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• 2008

The present study investigated the role of peripheral group I, II, and III metabotropic glutamate receptors (mGluRs) in mustard oil (MO)-induced nociceptive response in the masseter muscles of lightly anesthetized rats. Experiments were carried out on male Sprague-Dawley rats weighing 300-350 gm. After initial anesthesia with sodium pentobarbital (40 mg/kg, i.p.), one femoral vein was cannulated and connected to an infusion pump for intravenous infusion of sodium pentobarbital. The rate of infusion was adjusted to provide a constant level of anesthesia. MO (30 ${\mu}L$) was injected into the mid-region of the left masseter muscle via a 30-gauge needle over 10 seconds. After 30 mL injection of 5, 10, 15, or 20% MO into the masseter muscle, total number of hindpaw-shaking behavior was monitored. Intramuscular administration of MO significantly produced hindpawshaking behavior in a dose-dependent manner, as compared with the vehicle (mineral oil)-treated group. Intramuscular pretreatment with 10 or 100 ng DHPG, a group I mGluRs agonist, enhanced MO-induced hindpaw-shaking behavior, while APDC (20 or 200 ${\mu}g$), a group II mGluRs agonist, or L-AP4 (2 ${\mu}g$), a group III mGluRs agonist, significantly reduced MO-induced nociceptive behavior. The antinociception, produced by group II or III mGluRs agonists, was abolished by pretreatment with LY341495, a group II mGluRs antagonist, or CPPG, a group III mGluRs antagonist, res-pectively. Based on these observations, peripheral mGluRs differentially modulated MO-induced nociceptive behavior response in the craniofacial muscle pain and peripheral group II and III mGluRs agonists could be used in treatment of craniofacial muscle nociception.

• 대한소아치과학회지
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• 제23권3호
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• pp.717-728
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• 1996

The effects of electro-acupuncture on the pain threshold and the amplitude of dEMG(di-gastric EMG) evoked by the noxious electric stimulation on teeth and gingiva in dogs were studied. Experiments were carried out with 10 dogs weighing 5-8kg. Each animal was anestheticed with Entobar given intraperitoneally in an initial dose of 30mg/kg. Maintenance dose of 5mg/kg/hr was given through a cannula, in the femoral vein, as required to keep up light anesthesia. Bipolar stimulating wire electrodes, 0.1mm in diameter, insulated except for tips, were inserted into the upper canine and palatal gingiva. Rectangular aluminium plate electrodes (15$\times$5mm) were placed on acupuncture points, called Yin-Hsiang, located at both sides of the upper jaw. Rectangular biphasic current pulses of 2Hz, with a $250{\mu}sec$ duration, were delivered for 15 minutes. The dEMG activities were recorded from the anterior belly of the digastric muscle(one of the jaw opening muscles) using bipolar wire electrodes. The magnitude of the jaw opening reflex at different intensties of electro-acupuncture(1volt 4volt and 10volt) was estimated by averaging the 30 superimposed dEMGs recorded on an oscilloscope and audiomonitor. Data were analysed statistically with ANOV A and paired t-test. The obtained results were as follows: 1. Pain thresholds were increased 7.7 %, 15.4 %, 17.3 % in the teeth and 11.1 %, 19.0 %, 25.4 % in the gingiva as the intensities of electro-acupuncture increased incrementally. 2. Amplitudes of dEMG were decreaed 8.3%, 22.4%, 27.4% in the teeth and 9.8%, 36.5%, 42.2 % in the gingiva as the intensities of electro-acupuncture increased incrementally. 3. Inhibition of pain responses by the electroacupuncture was more effective in the gingiva than in the teeth.

• The Korean Journal of Physiology
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• 제16권2호
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• pp.177-186
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• 1982

The effect of ethacrynic acid (EA) on the renal secretion of PAH was examined in cat kidney. $C_{PAH}$ and $T_{PAH}$ were measured before and after infusion of EA $(0.5{\sim}50mg/kg)$ through the femoral vein. The following results were obtained: 1) In the dosage range of 0.5 to 25 mg/kg, EA increased the urine flow, and sodium and potassium excretion in dose-dependent manner, but the glomelular filtration rate was decreased as the dosage of EA was increased. 2) $C_{PAH}$ and $T_{PAH}$ were decreased by EA in the dosage range of 3 to 25 mg/kg and 1 to 50 mg/kg, respectively, in dose·dependent manner with the dosage to cause 50% inhibition of about 5 mg/kg. 3) With dosage of 0.5mg/kg, EA appeared to exert a great effect on diuretic response without the influence on $T_{PAH}$. At 10min after infusion of EA, a potent diuretic effect appeared, while $T_{PAH}$ did not show a significant change. These results suggest that the action mechanism of EA on tubular secretion of PAH may be different from that on natriuresis. 4) With dosage of 5 mg/kg, EA did not inhibit the Na-K-ATPase activity in microsomal fractions from both cortex and medulla. 5) The double reciprocal plot ($l/T_{PAH}$ versus $l/P_{PAH}$) suggested that EA inhibited the P AH secretion by a competitive pattern. However, probenecid, a prototypic inhibitor of the organic acid pump, had no influence on both the inhibitory effect of $T_{PAH}$ and the natriuretic effect by EA. These results suggest that in vivo EA altered tubular secretion of P AH through interactions with receptors that are not identical with the Na-K-ATPase.

• Archives of Plastic Surgery
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• 제40권3호
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• pp.214-219
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• 2013

Background We established the Microvascular Research Center Training Program (MRCP) to help trainee surgeons acquire and develop microsurgical skills. Medical students were recruited to undergo the MRCP to assess the effectiveness of the MRCP for trainee surgeons. Methods Twenty-two medical students with no prior microsurgical experience, who completed the course from 2005 to 2012, were included. The MRCP comprises 5 stages of training, each with specific passing requirements. Stages 1 and 2 involve anastomosing silicone tubes and blood vessels of chicken carcasses, respectively, within 20 minutes. Stage 3 involves anastomosing the femoral artery and vein of live rats with a 1-day patency rate of >80%. Stage 4 requires replantation of free superficial inferior epigastric artery flaps in rats with a 7-day success rate of >80%. Stage 5 involves successful completion of one case of rat replantation/transplantation. We calculated the passing rate for each stage and recorded the number of anastomoses required to pass stages 3 and 4. Results The passing rates were 100% (22/22) for stages 1 and 2, 86.4% (19/22) for stage 3, 59.1% (13/22) for stage 4, and 55.0% (11/20) for stage 5. The number of anastomoses performed was $17.2{\pm}12.2$ in stage 3 and $11.3{\pm}8.1$ in stage 4. Conclusions Majority of the medical students who undertook the MRCP acquired basic microsurgical skills. Thus, we conclude that the MRCP is an effective microsurgery training program for trainee surgeons.

• 대한한방내과학회지
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• 제20권1호
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• pp.111-121
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• 1999

Cervus elaphus (CE), being known to reinforce Kidney, have tested to study the effects concerning damages of renal tissue induced by oxygen free radicals. I had observed the effects of CE extract on damages of rat's kidney following ischemia and reflow. Before ischemia was caused, CE extract was applied $0.2m{\ell}$ per 250g through femoral vein in ischemia and reflow group and normal sailine was applied in normal group, Ischemia was caused by renal artery's clamp for 60 min and reflowed by clamp remove after 30 min. It was increased on the content of lipid peroxidation, activies and type conversion ratio of xanthine oxidase following ischemia and reflow. by clamp remove after 30 min. It was increased on the content of lipid peroxidation, activies and type conversion ratio of xanthine oxidase following ischemia and reflow. However, they were decreased when CE extract was pre-applied. Glutathione level was decreased in ischemia and reflow group, and increased in CE extract's pre-applied group. However, it could not seen special changes on aldehyde oxidase activities, either. In conclusion, CE extract recovers the damage of kidney due to ischemia and reflow by decreasing the lipid peroxidation.

• Biomolecules & Therapeutics
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• 제4권4호
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• pp.349-353
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• 1996

The present study examined pharmacokinetic profiles of KBP31705-Cl27 and KBP30603-901, new platinum coordination complexes synthesized as anticancer candidates, in comparison with two well-known platinum-containing anticancer agents, cisplatin and carboplatin in rats. Under sodium pentobarbital anesthesia of male Sprague-Dawley rats, urinary bladder, and femoral artery and vein were catheterized for urine collection, blood sampling and drug injection, respectively Following i.v. administration of cisplatin (2 mg/kg), KBP31705-C127 (2 mg/kg), carboplatin (20 mg/kg) or KBP30603-901 (20 mg/kg), blood samples were collected at 2, 4, 6, 8, 10, 15, 20, 30, 45, 60 and 120 minutes. Urine samples were collected at 1-hr interval for 4 hr. Platinum concentrations in plasma and urine were measured using an inductively coupled plasmamass spectrometer. The plasma concentration-time curves were biphasic for all drugs during the time period studied. Compared with cisplatin, KBP31705-C127 showed similar decay patters in the alpha- and betaphases with slightly lower plasma concentrations. Urinary platinum excretion for cisplatin and KBP31705-C 127 was 56 and 52% of the administered dose in 4 hr, respectively. With regard to carboplatin and KBP 30603-901, a similar decay pattern was also observed in the alpha-phase. The half life of KBP30603-901 in the beta-phase, however, was much longer than that of carboplatin, which was consistent with the urinary excretion results that 46 and 59% of the administered dose were excreted in the urine in 4hr, respectively. The results suggest that platinum coordination complexes are primarily excreted via the renal route and KBP30603-901 can elicit longer duration of action due to slower renal excretion compared to carboplatin.