• Journal of Pharmaceutical Investigation
• /
• v.8 no.1
• /
• pp.6-16
• /
• 1978

We obtained 4 kinds of extract fraction from Acanthopanacis Radicis Cortex and studied on the influence to the blood pressure of rabbit. These 4 fractions were obtained as follows; Fraction I was insoluble fraction by 99% ethanol from 80% methanol extract of Acanthopanacis Radicis Cortex, fraction II, precipitated fraction by ether from 99% ethanol soluble fraction of 80% methanol extract of Acanthopanaacis Radicis Cortex, fraction III, no precipitated fraction by ether from 99% ethanol soluble fraction of above 80% methanol extract and fraction IV, water extract of Acanthopanacis Radicis Cortex. All of fractions, when administered into ear-vein of rabbit, produced fall of blood pressure. Among these 4 fractions, although fraction III was not only the most potent but had the greatest efficacy, we observed the mechanism of hypotensive action of Acanthopanacis Radicis Cortex, making use of fraction II which was thought as a comparatively pure fraction. Hypotensive action of fraction II (APF II) was not affected by vagotominization but markedly inhibited by atropine. Pretreatment of bethanidine showed a tendency to weaken the depressor action of APF II, although it was not a significant result, but diphenhydramine did not influence APF II action. Phentolamine, guanethidine and chlorisondamine inhibited significantly the hypotensive action of APF II. APF II elicited the potentiation of norepinphrine pressor action dependent on the time-factor whereas it did not influence angiotesin pressor action. It is seemed that APF II exhibited hypotensive action, causing peripheral muscarinic-effect and centrally induced sympatholytic action.

• Journal of Pharmaceutical Investigation
• /
• v.8 no.1
• /
• pp.17-26
• /
• 1978

Effects of Acanthopanax EtOH Extract (AEE) on the serum total cholesterol content of normal and cholesterol administered rabbits were investigated as a series of studies on pharmacological action, especially blood pressure to Korean Acanthopanax. AEE was administered orally(100mg/kg/day) and subcutaneously (30mg/kg/day) in both normal and cholesterol administered rabbits for 36 days. In this experiment the results obtained by comparing with values of the corresponding control group were as follows; 1) In the normal rabbits, long-term administration of AEE for 36 days did not entirely influence the serum total cholesterol content measured at 12th, 24th and 36th day and also not affect the original blood pressure and changes of blood pressure to norepinephrine, angiotensin and acetylcholine recorded at 36th day. 2) In the cholesterol administered rabbits, hypercholesteremia was induced by oral administration of cholesterol(300mg/kg/day) with feed. The rise rate of serum total cholesterol content was not modified at 12th day, whereas significantly inhibited at 24th and 36th days after begining this examination in both groups orally and subcutaneously administered AEE. Original blood pressure was declined and depressor action of acetylcholine was weakened in only group admininstered orally AEE of cholesterol-fed groups. Changes of blood pressure to norepinephrine and angiotensin in these all cholesterol-fed groups, and to acetylcholine in subcutaneous group of these cholesterol-fed groups were not affected significantly by AEE.

• The Korean Journal of Pharmacology
• /
• v.25 no.1
• /
• pp.31-42
• /
• 1989

The effect of metoclopramide (MCP), which is well-known as a selective dopaminergic antagonist used in treating esophageal refulx, gastroparesis and emesis induced by anticancer chemotherapy, on secretion of catecholamines (CA) in the perfused isolated rat adrenal gland was investigated. MCP given into an adrenal vein produced the dose-related increase in CA secretion from the adrenal gland. The secretory effect of CA evoked by MCP was inhibited markedly by atropine-pretreatment. but only partially blocked when chlorisondamine was added. The secretion of CA induced by MCP was potentiated by pretreatment with physostigmine, adenosine or ouabain. However, MCP-induced CA secretion was suppressed significantly by perfusion of calcium-free Krebs solution containing 5 mM-EGTA for 30 min. Perfusion of MCP (200 ug/30 min.) attenuated the secretory effect of CA evoked by potassium chloride or acetylcholine. These experimental results demonstrate that metoclopramide releases CA significantly by a calcium-dependent exocy totic mechanism. It is thought that the secretory effect of metoclopramide is due to activation of cholinergic muscarinic receptors present in the adrenal gland rather than nicotinic receptors and partly to the direct action on the chromaffin cell itself.

• The Korean Journal of Pharmacology
• /
• v.28 no.1
• /
• pp.27-40
• /
• 1992

The purpose of the present study is an attempt to investigate the effect of intraventricular taurine, which is a naturally occuring amino acid containing sulfur and has inhibitory action in brain, on heart rate and blood pressure in the urethane anesthetized rabbits and also to elucidate the mechanism of its cardiovascular actions. Taurine $(0.15{\sim}1.5\;mg)$ injected into the lateral ventricle of anesthetized normontensive rabbits produced a dose-related fall in arterial blood pressure and heart rate, which were marked and long-lasting along with considerable respiratory depression. However, the intravenous administration of taurine at the same dose with intraventricular injection did not induce any changes in blood pressure as well as heart rate. Depressor responses induced by taurine were inhibited significantly by pretreatment with chlorisondamine, clonidine, strychnine and bicuculline but not by atropine, vagotomy, propranolol and metoclopramide. Moreover, taurine did not affect the pressor responses of norepinephrine. Taurine-induced bradycardic effects were blocked clearly by pretreatment with chlorisondamine, propranolol, clonidine, strychnine and bicuculline, while they were not influenced by atropine, vagotomy and metoclopramide. These experimental results suggest that intraventricular taurine causes long-lasting hypotensive and bradycardic actions, and that these cardiovascular effects may be exerted through taurinergic (glycinergic) and GABAergic receptors which are associated with catecholaminergic neurons in brain.

• The Korean Journal of Pharmacology
• /
• v.27 no.2
• /
• pp.167-181
• /
• 1991

The present study was an attempt to investigate the effect of forskolin on secretion of catecholamines (CA) evoked by Ach, excess $K^+$, DMPP, McN-A-343 and caffeine from the isolated perfused rat adrenal glands and to elucidate its mechanism of action. The perfusion with forskolin (1.0 uM) for 1 min into the adrenal vein enhanced markedly the secreation of CA evoked by Ach (50 ug), excess $K^+$ (56 mM) DMPP (100 uM) and by caffeine (0.3 mM) but did not that by McN-A-343. Forskolin alone did not potentiate the CA secretion. Moreover, forskolin augmented the CA release evoked by the above same stimulation even in the absence of extracellular calcium. The 1 min perfusion of 300 uM-dibutyryl cyclic AMP (DBcAMP), which is known to increase cyclic AMP levels, led to enhancement of Ca secretion evoked by Ach, excess $K^+$ and DMPP but did not that by McN-A-343 and caffeine. DBcAMP by itself also did not augment the CA secretion. In the calcium-free medium DBcAMP significantly enhanced the CA secretion by the same stimulation, except for the case of McN-A-343. These experimental results suggest that forskolin activates adenylate cyclase, resulting the elevation of cyclic AMP which may potentiate cholinergic nicotinic receptor-mediated and also depolarization-dependent CA secretion and that it may alter the intracellular calcium homeostasis in the rat adrenal glands.

• The Korean Journal of Pharmacology
• /
• v.24 no.1
• /
• pp.31-42
• /
• 1988

The effect of Panaxadiol(PD), which is an active component of Korean Ginseng Saponins, on the secretion of catecholamines (CA) from the rabbit adrenal gland and its mode of action were investigated in the present study. $PD(400{\mu}g)$ increased significantly the secretion of CA from the isolated perfused rabbit adrenal gland. PD-induced secretion of CA was reduced markedly by treatment of atropine, CA secretion induced by Ach or PD was potentiated significantly by physostigmine-treatment. Chlorisondamine did inhibit CA secretion of PD or Ach. Perfusion of $PD(400{\mu}g)$ for 30 min enhanced the secretory activity of CA by Ach. Ouabain weakened the secretory response induced by PD but rather enhanced the response by Ach. Adenosine-treatment resulted in marked enhancement of CA secretion by PD or Ach, Pefusion with $Ca^{2+}-free$ Krebs containing EGTA (5 mM) for about 30 min totally blocked secretory effect induced by Ach and also weakened that by PD. From the above experimental results, it is suggested that PD causes secretion of catecholamines from the rabbit adrenal gland by a calcium-dependent exocytotic mechanism. The secretory effect of PD is due to the stimulation of cholinergic muscarinic and nicotinic receptors present in the adrenal gland and partly to a direct action on the chromaffin cell itself.

• The Korean Journal of Pharmacology
• /
• v.28 no.2
• /
• pp.181-190
• /
• 1992

The present study was conducted to investigate the effect of opioids on catecholamine (CA) secretion evoked by a selective cholinergic nicotinic agonist, 1,1-dimethyl-4-phenyl piperazinium (DMPP) and acetylcholine from the retrogradely perfused rat adrenal glands. Methionine-enkephalin $(9.68{\times}10^{-6}\;M)$ caused a significant inhibition of CA secretion evoked by DMPP (100 uM) and $ACh\;(50\;{\mu}g)$, but had no effect on the spontaneous (basal) CA release. Morphine $(1.73{\times}10^{-5}\;M)$ attenuated considerablely the increase in CA release induced by DMPP and ACh. Morphine itself also did not affect the basal CA output. A 20 to 65% reduction of the DMPP- and ACh-evoked increase in CA release was observed after the pretreatment with methionine-enkephalin or morphine. The increase in CA release evoked by DMPP and ACh was reduced markedly by preloading with an opiate antagonist naloxone $(1.22{\times}10^{-7}\;M)$ while basal CA output was not affected by naloxone. These present experimental results suggest that the nicotinic stimulation-evoked CA release from the perfused rat adrenal gland is inhibited by endogenously released opioid peptides through activation of opiate receptors located in the adrenal gland.

• Journal of Pharmaceutical Investigation
• /
• v.8 no.3
• /
• pp.16-23
• /
• 1978

This study was carried out for the purpose of observing the effect of Korean Acanthopanax Radicis Cortex on renal hypertension and to clarify the mechanism of this effect, making use of its ethanol extract. Adult male or female rats, weighing 180-250g, were divided into 3 groups; the first for normotensive control, the second for hypertensive control and the third for hypertensive Acantopanax-treatment. Rats in the normotensive and hypertensive control group were administered 0.9% saline subcutaneously only, whereas those in the Acanthopanax-treated hypertensive group were administered 50mg/kg Acanthopanax ethanol extract subcutanously once a day. Changes of original blood pressure, and responses of blood pressure to various 4gents(norepinephrine, angiotensin, acetylcholine, serotonin and histamine) were recorded for each group on the initial, 18th, 32nd and 46th days of the experiment. The results obtained in this experiment are as follows: 1) The initial blood pressure was $102.6{\pm}7.6mmHg$ on the average. The blood pressures of the normotensive control group were not observed to alter significantly at any period in the course of the experiment. 2) The mean blood pressures in the hypertensive control group were recorded at $120.3{\pm}10.4mmHg$ on the 18th day, at $134.5{\pm}9.2$ on the 32nd day and at $138.8{\pm}8.3$ on the 46th day, thus revealing significant elevation in comparison with the corresponding normotensive control group blood pressures. On the other hand, the mean blood pressures in Acanthopanax-treated hypertensive group on the 18th, 32nd and 46th days were $118.3{\pm}9.7,\;129.9{\pm}8.3\;and\;120.2{\pm}8.3mmHg$ respectively. The blood pressures of the hypertensive-Acanthopanax group recorded. on the 46th day revealed a significant difference as compared with those of the corresponding hypertensive control group. 3) On the 46th day of this experiment, the responses of blood pressure to acetylcholine in the hypertensive-Acanthopanax group were suppressed significantly as compared with those of the hypertensive control group, and in the latter group, angiotensin was decreased markedly as compared with the corresponding normotensive control group. In contrast, pressor action of norepinephrine and depressor action of serotonin and histamine did not differ significantly among the three groups. These results suggest that Acanthopanax ethanol extract suppresses the induction of renal hypertension by means of a cholinergic action such as that caused by acetylcholine.

• The Korean Journal of Pharmacology
• /
• v.32 no.1
• /
• pp.83-91
• /
• 1996

The present study was designed to determine the effect of hydrocortisone on CA secretion evoked by histamine from the isolated perfused rat adrenal glands. Histamine (150 ug) given into an adrenal vein produced significantly CA secretion from the rat adrenal medulla. This histamine-evoked CA secretion was enhanced markedly by the pretreatment with the natural glucocorticoid hydrocortisone (30 uM) or the synthetic glucocorticoid dexamethasone 30 (uM) for 20 min, respectively. Hydrocortisone-induced potentiation of CA secretion evoked by histamine was inhibited by preloading with heparin (3.56 U/ml), an $IP_3$ receptor antagonist while more enhanced by forskolin (0.2 uM), a potent stimulator of adenylate cyclase. From the experiment result taken together, it is thought that hydrocortisone (glucocorticoids) can enhance the releasing effect of CA evoked by histamine from the isolated perfused rat adrenal medulla, which seems to be associated to accumulation of inositol phosphate as well as cyclic AMP in the rat adrenomedullary chromaffin cells.

• The Korean Journal of Pharmacology
• /
• v.27 no.1
• /
• pp.53-67
• /
• 1991

The characteristics and differences between DMPP and McN-A-343 on the secretory effect of catecholamines(CA) were studied in the isolated perfused rat adrenal glands. DMPP(100 uM) and McN-A-343(100 uM) perfused into an adrenal vein of the gland casued significant increases in CA secretion. On molar basis the secretory effect of McN-A-343 was about one fifth as potent as that of DMPP. Tachyphylaxis to releasing effects of CA evoked by DMPP and McN-A-343 was not observed by repeated perfusion of these agents. The DMPP-evoked CA secretion was significantly inhibited by pretreatment with chlorisondamine, desipramine and profusion of $Ca^{2+}-free$ Krebs solution containing EGTA, while it was not affected by pirenzepine, ouabain and physostigmine. However, pretreatment with atropine rather enhanced CA release by DMPP. The releasing effect of CA induced by McN-A-343 was markedly depressed by pretreatment with atropine, pirenzepine, chlorisondamine, physostigmine, and perfusion of $Ca^{2+}-free$ medium plus EGTA but was not influenced by desipramine, except for the case of ouabain which clearly potentiated CA release by McN-A-343. These experimental results suggest that both DMPP and McN-A-343 cause greatly secretion of CA from the isolated perfused rat adrenal glands by a calcium-dependent exocytotic mechanism. The secretory effect of DMPP is due to the stimulation of cholinergic nicotinic receptors and the secretion by McN-A-343 via activation of selecive $M_{1}-muscarinic$ receptors in the adrenal gland. It is also thought that the DMPP-evoked secretory effect is much greater than McN-A-343-induced effect.