Biomedical subjects

M T Hsieh

Publications and source records attributed to M T Hsieh.

At least 19 recordsLinked to original sources

PubMed1998

Ameliorating effect of p-hydroxybenzyl alcohol on cycloheximide-induced impairment of passive avoidance response in rats: interactions with compounds acting at 5-HT1A and 5-HT2 receptors.

The effect of p-hydroxybenzyl alcohol (HBA) on cycloheximide (CXM)-induced impairment in the step-through passive avoidance task was investigated in rats and compared to the effect of the nootropic piracetam. HBA and piracetam significantly counteracted the CXM-induced shortening of retention latencies. The effect of HBA was a bell-shaped dose-response curve with a maximal effect of 5 mg/kg. The counteractive effect of HBA was not depressed by either scopolamine or mecamylamine. The serotonin (5-HT) releaser, p-chloroamphetamine, and presursor, 5-hydroxytryptophan, significantly antagonized the counteractive effect of HBA on the CXM-induced shortening of retention latencies. Furthermore, the counteractive effect was also inhibited by the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and the 5-HT2 receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2 aminopropane [(+/-)-DOI], but potentiated by the 5-HT1 receptor antagonist (+/-)-pindolol and the 5-HT2 receptor antagonist ritanserin. There results suggest that the beneficial effect of HBA on CXM-induced impairment is amplified by treatment with serotonergic receptor antagonists but reduced by serotonergic 5-HT1A and 5-HT2 receptor agonists, and insensitive to cholinergic manipulations.

Animals↗

PubMed1998

Magnolol decreases body temperature by reducing 5-hydroxytryptamine release in the rat hypothalamus.

1. The effects of magnolol, isolated and purified from the cortex of Magnolia officinalis Rehd. et Wils, on thermoregulation and hypothalamic release of 5-hydroxytryptamine (5-HT) by in vivo microdialysis were assessed in normothermic rats and in febrile rats treated with interleukin-1 beta. 2. Intraperitoneal administration of magnolol (25-100 mg/kg) produced a decrease in colon temperature, an increase in foot skin temperature, a decrease in metabolic rate and a decrease in the endogenous release of 5-HT in the rat hypothalamus. 3. Depletion of rat brain 5-HT, produced by intracerebroventricular pretreatment with 5,7-dihydroxytryptamine, attenuated the magnolol-induced hypothermia, cutaneous vasodilation and decreased metabolism. 4. Intracerebroventricular administration of (+/-)-2,5-dimethoxy-4-iodoamphetamine (a 5-HT2 receptor agonist; 5-10 micrograms/5 microL) increased basal colon temperature and reversed the magnolol-induced hypothermia. 5. The increases in both colon temperature and hypothalamic 5-HT release produced by interleukin-1 beta injection were attenuated by treatment with magnolol. 6. The data suggest that magnolol decreases body temperature (due to increased heat loss and decreased heat production) by reducing 5-HT release in rat hypothalamus.

Animals↗

PubMed1997

Gastrodin and p-hydroxybenzyl alcohol facilitate memory consolidation and retrieval, but not acquisition, on the passive avoidance task in rats.

Gastrodin (GAS) and p-hydroxybenzyl alcohol (HBA) which is an aglycone of gastrodin, are active ingredients of Gastrodia elata Blume. In this study, we attempted to investigate the effects of acute administration of GAS and HBA on learning and memory processes such as acquisition, consolidation and retrieval, on the passive avoidance task in rats; piracetam was used as a positive control. Scopolamine, impairing learning acquisition, shortened the step-through latency in the retention test in rats. GAS and HBA did not prolong the step-through latency induced by scopolamine in the passive avoidance task, but piracetam could prolong the step-through latency induced by scopolamine. Cycloheximide, impairing memory consolidation, shortened the step-through latency in the retention test in rats. GAS at 50 mg/kg, HBA at 5 mg/kg and piracetam at 100 mg/kg could prolong the step-through latency induced by cycloheximide in the passive avoidance task. Apomorphine, impairing memory retrieval, shortened the step-through latency in the retention test in rats. GAS at 5 mg/kg, HBA at 1 mg/kg and piracetam at 300 mg/kg could prolong the step-through latency induced by apomorphine in the passive avoidance task. From the above results, we concluded that the facilitating effects of HBA on learning and memory are better than those of GAS. In conclusion, GAS and HBA can improve cycloheximide- and apomorphine-induced amnesia, but not scopolamine-induced acquisition impairment in rats. Thus, GAS and HBA can facilitate memory consolidation and retrieval, but not acquisition. The facilitating effects of GAS and HBA are different from those of piracetam.

Animals↗

PubMed1997

Biphasic effects of pu-chung-i-chi-tang on sedation and excitation.

The biphasic effects of Pu-Chung-I-Chi-Tang (PCT) on sedation and excitation in acute treatment or after one-week consecutive treatment were studied. The results indicated that PCT produces sedation in acute treatment and excitation after one-week consecutive treatment. The sedative mechanism of PCT in acute treatment might be due to an increase in serotonergic activity and a decrease in dopaminergic activity. However, the excitatory mechanism of PCT after one-week consecutive treatment might involve the increase in dopaminergic activity and the decrease in serotonergic activity.

Animals↗

PubMed1997

Effect of long-term administration of berberine on scopolamine-induced amnesia in rats.

The effect of berberine (BER) on scopolamine (SCOP)-induced amnesia was investigated in a step-through passive avoidance task in rats. It was observed that BER at the doses of 0.1 and 0.5 g/kg after 7-day or 14-day administration significantly improved SCOP-induced amnesia. The anti-amnesic effect of BER after 14-day administration on the SCOP-induced amnesia was significantly augmented by physostigmine or neostigmine, and completely reversed by scopolamine N-methylbromide. These results suggest that the antiamnesic effect of BER after 14-day administration may be related to the increase in the peripheral and central cholinergic neuronal system activity.

Amnesia↗

PubMed1996

Increase of locomotor activity by acupuncture on Bai-Hui point in rats.

The effect of acupuncture on locomotor activity was investigated in rats. Stimulation with acupuncture inserted in Bai-Hui point, which is located at the vertex of the head, increased the spontaneous locomotor activity of rats measured in ANIMEX meter. This effect was obtained in rats which received acupuncture significantly at 60 min later as compared with sham-treated control. The sleeping time induced by hexobarbital was also reduced markedly in rats receiving acupuncture. An activation of the central nervous system by acupuncture at Bai-Hui point can thus be considered. This action was unrelated to opioids because naloxone failed to modify it. Increase in locomotor activity was abolished by an intraperitoneal (i.p.) injection of alpha-methyl-p-tyrosine (200 mg/kg) at 2 h before insertion of acupuncture. Deprenyl at the dose sufficient to elevate monoamine enhanced this action of acupuncture. Mediation of cerebral monoamines can also be considered. This view was supported by the dose-dependent inhibition of chlorpromazine. Action of acupuncture was not observed in apomorphine (0.5 mg/kg, i.p.)-treated rats, probably due to an activated receptor of dopamine. Otherwise, action of acupuncture was enhanced by para-chlorophenylalanine, the depleter of endogenous 5-hydroxytryptamine (5-HT), and eliminated by 5-hydroxytryptophan, the precursor of 5-HT, in the initial stage of insertion. Participation of 5-HT can be considered as an initial way in rats that received acupuncture at Bai-Hui point. These results suggested that stimulation of Bai-Hui point with acupuncture can activate central neurotransmission of monoamines to increase the spontaneous locomotor activity in rats.

Acupuncture Points↗

PubMed1996

Effects of Hemerocallis flava on motor activity and the concentration of central monoamines and its metabolites in rats.

In this study, we used behavioral and biochemical methods to investigate the effects of Hemerocallis flava (Liliaceae) (abbreviated as HF) on motor activity and the concentration of monoamines in rats. The water fraction of the resuspended HF extract was most active in reducing the motility in rats. The water fraction of the HF extract enhanced the reduction of locomotor activity produced by alpha-methyl-p-tyrosine and 5-hydroxytryptophan, but it reduced the increase of locomotor activity produced by L-dopa plus benserazide and p-chlorophenylalanine. Furthermore, the water fraction of the HF extract significantly decreased the concentration of norepinepherine in the cortex and the concentration of dopamine and serotonin in the brain stem. It also increased the concentration of vanilylmandelic acid in the cortex, homovanillic acid and 5-hydroxyindole-acetic acid in the brain stem. These results suggest that the reduction of locomotor activity produced by the water fraction of HF extract may be related to the decrease in the concentration of norepinepherine in the cortex and the concentration of dopamine and serotonin in brain stem.

5-Hydroxytryptophan↗

PubMed1996

Effects of Gastrodia elata and its active constituents on scopolamine-induced amnesia in rats.

The effects of the rhizome of Gastrodia elata Blume (Orchidaceae) (abbreviated as GE) and its active constituents on learning and memory by using the one-trial passive avoidance task were studied in rats. At the 1.0 g/kg dose administered for one week, the methanol extract of GE significantly prolonged the shortened step-through latency induced by scopolamine in the passive avoidance task. Furthermore, at the 50.0 mg/kg dose administered for one week, the ethyl acetate and n-butanol fractions of the methanol extract prolonged the shortened step-through latency induced by scopolamine in rats. Gastrodin, isolated from the n-butanol fraction of the methanol extract, and p-hydroxybenzyl alcohol, isolated from the ethyl acetate fraction of the methanol extract, also significantly prolonged the shortened step-through latency induced by scopolamine on the passive avoidance task. These results suggested that gastrodin and p-hydroxybenzyl alcohol may be the active constituents of GE.

Amnesia↗

PubMed1996

Antihypertensive effects of DL-tetrahydropalmatine: an active principle isolated from Corydalis.

1. The effects of DL-tetrahydropalmatine (DL-THP) on cardio-vascular function and hypothalamic release of monoamines were assessed in rats under urethane anaesthesia. 2. Intravenous administration of DL-THP (1-10 mg/kg) produced hypotension, bradycardia, a decrease in hypothalamic serotonin and noradrenaline release and an increase in hypothalamic dopamine release in rats. 3. Intrahypothalamic administration of DOI (a serotonergic 5-HT2 receptor antagonist) or apomorphine (a dopamine D2-receptor agonist) produced the opposite effects and reversed DL-THP-induced hypotension and bradycardia. 4. The data suggest that DL-THP acts through the 5-HT2 and/or D2-receptor antagonism in the hypothalamus to induce hypotension and bradycardia in rats.

Amphetamines↗

PubMed1996

Inhibitory effects of (+/-)-tetrahydropalmatine on thyrotropin-stimulating hormone concentration in hyperthyroid rats.

The effects of (+/-)-tetrahydropalmatine ((+/-)-THP) on the hypothalamus-pituitary-thyroid system in rats were investigated. Thyroid function experiments indicated that (+/-)-THP produces significant decreases in thyroid function in hyperthyroid rats after 14 days of treatment. These effects were the same as those of propylthiouracil. However, propylthiouracil also decreased thyroid function in normal rats. Measurements of thyrotropin-stimulating hormone (TSH) demonstrated that (+/-)-THP decreased TSH in hyperthyroid rats after 14 days of treatment; however, propylthiouracil increased TSH in hyperthyroid rats. (+/-)-THP had no influence on TSH, or thyroid and pituitary weight in normal and hyperthyroid rats. We conclude that (+/-)-THP has an antithyroid function and the mechanism of action may be related to the inhibition of TSH in the pituitary.

Animals↗

PubMed1996

p-Hydroxybenzyl alcohol attenuates learning deficits in the inhibitory avoidance task: involvement of serotonergic and dopaminergic systems.

p-Hydroxybenzyl alcohol (HBA), an aglycone of gastrodin, is an active ingredient of Gastrodia elata BLUME. In this study, we investigated the action of HBA on acquisition of an inhibitory avoidance response in rats and used piracetam as a positive control. The results indicated that scopolamine, a cholinergic receptor antagonist, injected before training impaired retention. HBA did not attenuate the scopolamine-induced impairment, but piracetam did. p-Chloroamphetamine, a serotonin releaser, injected before training impaired retention. HBA at 5 mg/kg and piracetam at 100 mg/kg could counteract the p-chloroamphetamine-induced deficit. Apomorphine, a dopaminergic receptor agonist, also impaired retention. HBA at 5 mg/kg and piracetam at 300 mg/kg could ameliorate the apomorphine-induced amnesia. The above results indicated that HBA, different from piracetam, can attenuate impairments induced by p-chloroamphetamine and apomorphine, but had no effect on impairment induced by scopolamine in an inhibitory avoidance task in rats. Such findings suggest that HBA may act through suppressing dopaminergic and serotonergic activities and thus improves learning.

Animals↗

PubMed1995

Effects of ginseng on the blood chemistry profile of dexamethasone-treated male rats.

Ginseng, a panacea in the Orient, has been widely investigated in the last two decades and found to possess a wide range of pharmacological activities including anti-fatigue properties, a transient regulatory action on metabolism and blood pressure, and an increase in the hypothalamo-pituitary-adrenocortical activities. However, a panoramic clinical chemistry study including adrenal and thyroid functions has never been done before. Two experiments with the same design but different concentrations of dexamethasone were performed in this study. The results obtained from the two experiments indicated that ginseng administration at this regime did not influence the blood chemistry profiles in normal rats, but significantly decreased AST and ALT levels from those in dexamethasone-treated ones. It implies that ginseng has a liver-protective effect. Meanwhile, ginseng therapy restores the adrenal and thyroid functions of rats inhibited by dexamethasone treatment.

Animals↗

PubMed1995

DL-tetrahydropalmatine-produced hypotension and bradycardia in rats through the inhibition of central nervous dopaminergic mechanisms.

The effects of DL-tetrahydropalmatine (THP; a main active substance of the Chinese herb corydalis), haloperidol (a dopamine D2 receptor antagonist), apomorphine and amphetamine on cardiovascular function and striatal dopamine (DA) release were compared in rats under general anesthesia. Intravenous administration of THP (1-10 mg/kg) or haloperidol (0.5-1.25 mg/kg) produced hypotension, bradycardia and increased DA release in the striatum. On the other hand, amphetamine (0.5-1.25 mg/kg) produced hypertension, tachycardia and increased striatal DA release. However, intravenous injection of apomorphine (0.5-1.25 mg/kg) produced hypotension, bradycardia and decreased striatal DA release. In addition, the THP-induced hypotension was attenuated by pretreatment with spinal transection or amphetamine, while the THP-induced bradycardia was attenuated by pretreatment with bilateral vagotomy or amphetamine. Thus, it appears that THP acts through DA D2 receptor antagonism to induce hypotension and bradycardia in rats.

Amphetamine↗

PubMed1995

Hypotensive and bradycardic effects of dl-tetrahydropalmatine mediated by decrease in hypothalamic serotonin release in the rat.

In anesthetized rats, intravenous administration of dl-tetrahydropalmatine (dl-THP, 1-10 mg/kg) elicited proportional hypotension, bradycardia and decreases in hypothalamic serotonin (5-HT) release (measured by carbon-fiber electrodes in combination with voltammetry). In addition, postsynaptic blockade of 5-HT2 receptors with cyproheptadine (2-5 mg/kg, i.v.) or ketanserin (2-5 mg/kg, i.v.) produced both hypotension and bradycardia, while stimulation of 5-HT2 receptors with 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) (10-250 mg/kg, i.v.) produced both hypertension and tachycardia. The dl-THP-induced hypotension and bradycardia could be reversed by DOI treatment. The data indicate that dl-THP decreases both arterial pressure and heart rate through a serotonergic release process in the hypothalamus.

Adrenergic Agents↗

PubMed1994

Effects of DL-tetrahydropalmatine on motor activity and the brain monoamine concentration in rats.

Behavioral and biochemical methods were used in this study to investigate the effect of DL-THP on motor activity and the concentration of monoamines in rats. Experimental results indicated that DL-THP significantly decreased the motor activity of rats and showed a dose-response pattern; in addition, it produced rigidity at a higher dosage. DL-THP also enhanced the hypomotility induced by haloperidol, but reduced the hypermotility produced by apomorphine. Furthermore, DL-THP significantly decreased the concentration of norepinephrine (NE), dopamine (DA) in the cortex and brain stem at lower and higher dosages, and the concentration of serotonin (5-HT) in the cortex at higher dosages. DL-THP also increased the concentration of homovanillic acid (HVA) in the cortex and brain stem at lower and higher dosages, and the concentration of 5-hydroxyindole acetic acid (5-HIAA) in the cortex at higher dosages. These results suggest that the hypomotility produced by DL-THP may be due to the increase in the turnover rate of dopamine in the cortex and brain stem at lower and higher dosages, and of serotonin in the cortex at higher dosages.

Animals↗

PubMed1993

Effects of palmatine on motor activity and the concentration of central monoamines and its metabolites in rats.

We used behavioral and biochemical methods to investigate the sedative effect of palmatine on locomotor activity and the concentration of monoamine in rats. It was found that palmatine enhanced the hypomotility induced by alpha-methyl-p-tyrosine, reserpine and 5-hydroxytryptophan, but reduced the hypermotility produced by L-dopa plus benserazide and p-chlorophenylalanine. Furthermore, palmatine significantly decreased the concentration of dopamine and homovanillic acid in the cortex and the concentration of serotonin in the brain stem, and it increased the concentration of 5-HT in the cortex and 5-hydroxyindole acetic acid in the brain stem. These results suggest that the sedative mechanism of palmatine may be related to the decrease in the concentration of catecholamine in the cortex and serotonin in brain stem and the increase in the concentration of 5-HT in the cortex.

5-Hydroxytryptophan↗

PubMed1991

Studies on the anticonvulsive, sedative and hypothermic effects of Periostracum Cicadae extracts.

The anticonvulsive, sedative and hypothermic effects of water and ethanol extracts of Periostracum Cicadae (PC), the cast off skin of Cryptotympana atrata were studied. The water-extract of whole Periostracum Cicadae (PCws) had anticonvulsive, sedative and hypothermic effects in rats. Orally, it decreased carrageenin-induced hyperthermia. The hypothermic effect of PCws was potentiated by 5-hydroxytryptophan and antagonized by p-chlorophenylalanine. PCws enhanced the decrease in locomotor activity induced by alpha-methyl-p-tyrosine or 5-hydroxytryptophan and reduced the increase in locomotor activity produced by levodopa plus benserazide or p-chlorophenylalanine. From these results, it was concluded that the sedative and hypothermic effect of PCws may be due to an increase in central serotonergic activity.

Animals↗

PubMed1991

Isolation and typing of herpes simplex virus from clinical specimens collected at National Taiwan University Hospital, 1981-1990.

From 1981 to 1990, 10,167 clinical specimens were collected at National Taiwan University Hospital from the cases with suspected viral infections. Three hundred of herpes simplex virus (HSV) were isolated from these samples (isolation rate; 3.0%). One hundred and fifty-one strains were isolated from non-genital, and 149 strains from genital areas. HSV strains were typed by direct immunofluorescence staining technique. The type specific monoclonal antibodies were used in the test. Most of the HSV strains isolated from non-genital areas were type 1 (HSV-1) (147/151, 97.4%) whereas most of the strains from genital areas were type 2 (HSV-2) (140/149, 94.0%). All nine strains of HSV-1 isolated from genital areas were from female patients. The predominance of HSV-1 in non-genital area infections, and of HSV-2 in genital area infections, did not change during the ten years under review.

Female↗