• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.63-74
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• 1995

It has been known that, during hypoxia, the adrenal medulla is activated to release catecholamines (CA) while hypoxia also inhibits high $K^+$ -induced CA secretion in the cultured bovine adrenal chromaffin cells. The present study was attempted to examine the effect of hypoxia on CA secretion evoked by chlinergic stimulation and membrane-depolarization from the isolated perfused rat adrenal glands and also to clarify its mechanism of action. For this purpose, using the isolated rat adrenal glands, the effects of hypoxia on CA release evoked by nicotinic ($N_1$) and muscarinic ($M_1$) receptor agonists, membrane-depolarizing agent, $Ca^{++}$-channel activator, intracellular $Ca^{++}$-releaser and ACh were determined. Experiments were carried out, perfusing Krebs solution pre-equilibrated with a gas mixture of 95% N_2$ and 5% $CO_2$. Hypoxia was maintained for $3{\sim}4$ hours through the experiments. Hypoxia gradually caused a time-dependent seduction in CA secretion evoked by DMPP ($100{\mu}M$), McN-A-343 ($100{\mu}M$), ACh (5.32 mM), Bay-K-8644 ($10{\mu}M$) and high $K^+$ (56 mM) respectively. How-ever, it did not affect CA secretion evoked by cyclopiazonic acid ($10{\mu}M$). Hypoxia itself also did fail to produce any influence on spontaneous secretory response of CA. These experimental results suggest that hypoxia depresses CA release evoked by both cholinergic stimulation and membrane-depolarization from the isolated rat adrenal medulla, and that this inhibitory activity may be due to the result of the direct inhibition of $Ca^{++}$ influx into the chromaffin cells without any effect on the calcium mobilization from the intracellular store.

• The Korean Journal of Pharmacology
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• v.24 no.1
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• pp.93-101
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• 1988

Pharmacological actions of an antispasmodic agent, oxybutynin were investigated in the isolated procine coronary arteries. The coronary rings were contracted by acetylcholine (ACh) and KCl in a dose-dependent fashion. The ACh-induced contractions were signifcantly potentiated by removal of endothelium and $EC_{50}=0.52\;{\mu}M$ of intact endothelial rings was about 2 times greater than $EC_{50}=0.28\;{\mu}M$ of rings without the endothelium. These results suggest that the endothelium plays an inhibitory role in ACh-induced contraction. Oxybutynin and atropine inhibited dose-dependently $1.0\;{\mu}M$ ACh-induced contraction and atropine inhibited dose-dependently $1.0\;{\mu}M$ ACh-induced contraction and the $IC_{50s}$ were 11.0 nM and 0.47 nM, respectively. Atropine did not affect 35 mM KCl-induced contraction but oxybutynin inhibited the contraction to the basal tension in a dose-dependent manner. The $IC_{50}$ of oxybutynin on the KCl-induced contraction was $49.7\;{\mu}M$. The dose-response curve to ACh was parallelly shifted to the right by pretreating coronary rings with $IC_{50}$ of atropine (0.47 nM) or oxybutynin (11.0 nM) but the curve to KC1 was rightward shifted in a noncompetitive manner under pretreatment with $IC_{50}$ of oxybutynin $(49.7\;{\mu}M$). Oxybutynin inhibited $0.1\;{\mu}M$ Bay K 8644-induced contraction to the basal tension in a dose dependent manner, but $35\;{\mu}M$ histamine-induced contraction was inhibited to only 50e/e of the original level even in maximal concentration $(5{\times}10^{-4}M)$ of oxybutynin. These results suggest that oxybutynin causes antispasmodic action through sensitive blocking action on muscarinic receptors and inhibitory action on calcium influx in the procine coronary artery.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.2
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• pp.123-127
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• 1987

The Pungent principles and Essential oil compositions of Zanthoxylum piperitum $D_E$ $C_{ANDOLIE}$(peel, barb) were analysed by HPLC and GC, respectively. Total Pungent principle contents of peels were about as 12 times as those of barks. The Sanshool I, Sanshool IV, Sanshool III and Sanshoo V were the major Pungent principles in the peels and barks. Besides, several Unknown Pungent principles were discovered in the peels and barks, too. Total Essential oil contents of peels were higher than those of barks at the ratio of 1.8 % to 0.5%. The Cineol+Limonene(37.7%) were the main Essential oil compositions in the peels, while ${\alpha}-Terpineol(16.5%)$ and Pinene(15.5%) were the major portion in the barks. The Essential oil of peels and barks were composed Pinen, Myrcene, Cineol+Limonene, Linalool, Isopulegol, Terpinen-4-ol, ${\alpha}-Terpineol$ and Piperitone. Besides, seven Unknown compositions were discovered, too.