• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1996.04a
• /
• pp.217-217
• /
• 1996

The putative role of vasoactive intestinal polypeptide (VIP) as non-adrenergic non-cholinergic (NANC) neurotransmitter has been studied in rabbit corpus cavernosum. In the presence of atropine and guanethidine the short and prolonged electrical field stimulation (EFS, 2～16 ㎐) induced a frequency-dependent relaxation which was abolished by tetrodotoxin (0.3 ${\mu}$M), a nerve conductance blocker. The neurogenic relaxant reponses were not affected in the presence of VIP-inactivating peptidase, ${\alpha}$-chymotrypsin (2 units/$m\ell$), whereas VIP-induced relaxation were completely abolished. Inhibition of nitric oxide synthase by N$\^$G/-nitro-L-arginine (10～100 ${\mu}$M) caused concentration-dependent inhibition to the neurogenic relaxant responses and at 100 ${\mu}$M the relaxations were virtually abolished. In contrast NO (3～30 ${\mu}$M) and VIP (0.001～l ${\mu}$M)-induced relaxation were unaffected. The inhibitory effect of L-NNA was reversed in the presence of L-arginine (5 mM), the precursor of the NO biosynthesis. Hemog1obin (20～60 ${\mu}$M), sequestering NO in the extracellular space, abolished the NO-evoked relaxation and also caused a concentration-dependent inhibition to the neurogenic relaxation. These observation indicate that NANC relaxation induced by prolonged EFS of rabbit corpus cavernosum is also mediated mainly by nitric oxide as same as that of short EFS, and suggest that VIP is not involved in NANC relaxation of rabbit corpus cavernosum and NO would not be produced by VIP in this tissue.

• Korean Journal of Veterinary Research
• /
• v.43 no.4
• /
• pp.597-606
• /
• 2003

Although the antidepressant effects of imipramine (IMI) have been well known in several studies, the effects on cardiovascular system, particularly the vasorelaxant effects, have not known clearly. We hypothesis that IMI-induced vasorelaxation involves NO (nitrie oxide), activation of guanylate cyclase (GC) and $Ca^{2+}$ channel. The possible roles of the endothelium and $Ca^{2+}$ in IMI-induced responses were investigated using isolated rings of rat thoracic aorta and anesthesized rats. In KCl-precontracted rings. IMI produces endothelium-dependent and endothelium-independent relaxations in intact (+E) as well as endothelium-denuded (-E) rat aorta in a concentration-dependent manner. In phenylephrine (PE)-precontracted rings, the IMI-induced relaxation was significantly greater in +E rings. The IMI-induced relaxations were suppressed by nitric oxide synthase (NOS) inhibitors, N(G)-nitro-L-arginine (L-NNA), N(omega)-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine, a non-selective GC inhibitor, methylene blue, $Na^+$ channel blockers, lidocaine and procaine, or $Ca^{2+}$ channel blockers, nifedipine and verapamil, in PE-precontracted +E rings, but not in PE-precontracted -E rings. These relaxations were also suppressed by lidocaine or procaine in -E aortic rings. However, IMI-induced relaxations were not inhibited by a PLC inhibitor 2-nitro-4-carboxyphenyl-n,n-diphenylcarbamate (NCDC), an inositol monophosphatase inhibitor, lithium, indomethacin and dexamethasone in +E and -E rings. In vivo, infusion of IMI elicited significant decrease in arterial blood pressure. After intravenous injection of saponin, NOS inhibitors. MB and nifedipine, infusion of IMI inhibited the IMI-lowered blood pressure markedly. These findings suggest that the endothelium-dependent relaxation induced by IMI is mediated by activation of NO/cGMP signaling cascade or inhibition of $Ca^{2+}$ entry through voltage-gated channel, and this mechanism may contribute to the hypotensive effects of IMI in rats.

• Biomolecules & Therapeutics
• /
• v.12 no.1
• /
• pp.25-33
• /
• 2004

In this study we investigated whether ATP loss was involved in the potentiated death of immunostimulated rat primary astrocytes in glucose-deprived condition. Rat primary astrocytes immunostimulated with LPS plus IFN-${\gamma}$ for 48 h underwent death upon glucose deprivation, which dependent on the production of peroxynitrite. Intracellular ATP level synergistically decreased by glucose deprivation in immunostimulated astrocytes but not in control cells, and the loss of ATP occurred well ahead of the LDH release. The synergistic cell death and ATP loss by immunostimulation and glucose deprivation were inhibited by iNOS inhibitor (L-NAME and L-NNA) or peroxynitrite decomposition catalyst (also a superoxide anion scavenger), Mn(III)tetrakis(N-methyl-4'-pyridyl)porphyrin (MnTMPyP). Exogenous addition of peroxynitrite generator, SIN-l timedependently induced ATP loss and cell death in the glucose-deprived astrocytes. Depletion of intracellular glutathione (GSH) and dis겨ption of mitochondrial transmembrane potential (MTP) were also observed under same conditions. Supply cellular ATP by the addition of exogenous adenosine or ATP during glucose deprivation inhibited ATP depletion, GSH depletion, MTP disruption and cell death in SIN-l treated or immunostimulated astrocytes. This study showed that perturbation in the regulation of intracellular ATP level in immunostimulated astrocytes might make them more vulnerable to energy challenging stimuli.

• Korean Journal of Veterinary Research
• /
• v.44 no.3
• /
• pp.389-397
• /
• 2004

The therapeutic efficacy of xylamine in the field of psychological medicine has been recognized for years and the drug is used to treat depression and some other conditions, but little is known about its mechanism of action on vascular system. Therefore, the present study was designed to investigate the influence of xylamine on the contractile responses of isolated rat thoracic arteries to phenylephrine(PE) and potassium chloride(KCl). Xylamine produced a concentration-dependent relaxation in PE-precontracted endothelium intact(+E) rat aortic rings, but not in a KCl-precontracted aortic rings. Also, xylamine inhibited the PE-induced contraction in concentration-dependent manner, but not in the high KCl-induced contraction in +E rings. This concentration-dependent inhibition was suppressed by the removal of the endothelium (-E). The inhibitory effects of xylamine($0.3{\mu}M$) on the PE-induced contractions were suppressed by N(G)-nitro-L-arginine(L-NNA), N(omega)-nitro-L-arginine methyl ester(L-NAME), aminoguanidine, dexamethasone, methylene blue, 1H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one(ODQ), indomethacin, ryanodine, tetrabutylammonium(TBA), lidocaine, procaine and 0 mM extracellular $Na^+$, but not by 2-nitro-4-carboxyphenyl-n,n-diphenylcarbamate(NCDC), lithium, nifedipine, verapamil, 0 mM extracellular $Ca^{2+}$, glibenclamide and clotrimazole. These findings suggest that xylamine could act as a vasorelaxant and direct inhibitor of arterial contraction. This vasorelaxation involves an endothelial nitric oxide (NO)/cGMP (guanosine 3',5'-cyclic monophosphate) pathway or cyclooxygenase system, and an interference with $Ca^{2+}$ release, TBA-sensitive $Ca^{2+}$-activated $K^+$ channels and $Na^+$$ channels.

• Korean Journal of Medicinal Crop Science
• /
• v.5 no.4
• /
• pp.289-293
• /
• 1997

The effects of plant regulators on direct somatic embryogenesis in liquid culture of Rehmannia glutinosa were investigated and the proper explant for direct somatic embryo formation was studied. Direct somatic embryos were induced from leaf segments culture in the MS liquid medium containing 0.5 mg/l of both IAA and NAA, while IBA of 1.0 mg/l was required for the same effect. Many somatic embryos were directly formed at the concentration of 2.0 mg/l cytokinin such as BA, kinetin and zeatin, but somatic embryogenesis was relatively poor at above or below this level. Relatively more somatic embryos were induced in the combination of 1.0mg/l IAA and 2.0mg/l zeatin. Formation of somatic embryos begun after 6 weeks on stem segments, while 7 weeks both on petiole and leaf. However, overall production of somatic embryos after 8 weeks was higher in leaf segment than that of stem segment.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.4
• /
• pp.1036-1040
• /
• 2004

The purpose of the present study is to measure the effect of Tuber Pinelliae on EP(epinephrine) induced contraction of isolated rat thoracic aorta. Contractile force was measured with force displacement transducer under 1.5g loading tension. The mean percent increasing of rCBF was 11.4% (p<0.05) after 10㎎/㎏ Tuber Pinelliae. Contractions evoked by EP (ED50) and KCI 65.4mM were decreased significantly by Tuber Pinelliae. L-NNA, ODQ and atropine significantly altered the effect of Tuber Pinelliae, but propranolol and indomethacin did not change the relaxation of Tuber Pinelliae. These results indicate that Tuber Pinelliae can relax EP and KCI induced contraction of isolated rat thoracic aorta and that this decreasing contraction related to epithelium, nitric oxide, and parasympathetics.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.2
• /
• pp.457-462
• /
• 2004

Bambusae Caulis in Liquamen has been used as a herbal medicine for the treatment of heat, paralysis of the hands or feet, or hemiplegia. In the present study, we investigated the effect of Bambusae Caulis in Liquamen to the phenylephrine (PE) induced contraction of isolated rat aorta Contractile force was measured with force displacement transducer under 1.5 g loading tension. Contractions evoked by PE 0.1 μM were significantly increased by low dosage of Bambusae Caulis in Liquamen, decreased by high dosage of Bambusae Caulis in Liquamen. L-NNA, ODQ and propranolol significantly altered the effect of Bambusae Caulis in Liquamen, but indomethacin did not change the relaxation of Bambusae Caulis in Liquamen. These results suggest that Bambusae Caulis in Liquamen can relax EP induced contraction of isolated rat aorta and that this decreasing contraction related to sympathetics.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.5
• /
• pp.1299-1304
• /
• 2003

This study is to determine the effect of Fructus Rubi to the phenylehrine (PE) induced contraction of isolated rat aorta. Contractile force was measured with force displacement transducer under 1.5g loading tension. Contractions evoked by PE 0.1 μM and KCI 65.4 mM were decreased significantly by Fructus Rubi. L-NNA, ODQ, indomethacin and atropine significantly altered the effect of Fructus Rubi, but propranolol did not change the relaxation of Fructus Rubi. These results indicate that Fructus Rubi can relax EP and KCI induced contraction of isolated rat aorta and that this decreasing contraction related to epithelium, nitric oxide, and parasympathetics.

• The Journal of Internal Korean Medicine
• /
• v.23 no.1
• /
• pp.33-39
• /
• 2002

Objective : The objective of this study is to measure the changes of regional cerebral blood flow(rCBF) and blood pressure(BP) in rats with the following injection. Methods : The measurement was continually monitored by laser-doppler flowmeter-Transonic Instrument, USA- and pressure tranducer(Grass, USA) in anesthetized adult Sprague-Dawley rats about for two hour to two hour and a half hours through the data acquisition system composed of Maclab and Macintosh computer. Result : This experiment with Samso-eum increased the changes of rCBF in rats, significantly, but did not change the blood pressure. The rCBF of Samso-eum decreased by pretreated propranolol, and was not changed by pretreated L-NNA and ODQ. Conclusion : It is considered that the dosage-dependent increase on rCBF is mediated by adrenegic ${\beta}$-receptor.

• Journal of Life Science
• /
• v.11 no.1
• /
• pp.62-69
• /
• 2001

This study was aimed to investigate the effect Chukdamtanggamibang on the vascular systems including changes in blood pressure and regional cerebral blood flow(rCBF) of male Sprague-Dawely rats, contractile force of guinea pig`s tracheal smooth muscle and abdominal aorta and femoral artery in rabbits. Blood pressure was not affected by Chukdamtanggamibang in rats. rCBF was significantly increased by Chukdamtanggamibang in a dose-dependent manner. Contractile force of isolated guinea pig`s tracheal smooth muscle evoked by His ({TEX}$ED_{50}${/TEX}) were inhibited significantly by Chukdamtanggamibang. Propranolol, indomethacin and methylene blue did not significantly alter the inhibitory effect of Chukdamtanggamibang. Contractile force of isolated rabbit`s abdominal aorta and femoral artery evoked by NE ({TEX}$ED_{50}${/TEX}) were inhibited significantly by Chukdamtanggamibang. ODQ and L-NNA significantly attenuated the inhibitory effects of Chukdamtanggamibang in abdominal aorta, whereas propranolol did not significantly alter the inhibitory effect of Chukdamtanggamibang. These results indicate that Chukdamtanggamibang can relax hitamine-induced contraction of guinea pig`s tracheal smooth muscle and that this inhibition involves, in part, the relation to the soluble guanylyl cyclase synthesis and nitric oxide (NO) synthesis.