• Journal of Yeungnam Medical Science
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• v.12 no.2
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• pp.246-259
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• 1995

This study aimed to investigate the mechanism of action of baclofen on the detrusor muscle isolated from rat. Rats (Sprague-Dawley) were sacrificed by decapitation and exsanguination. Horizontal muscle strips of $2mm{\times}15mm$ were prepared for isometric myography in isolated muscle chamber bubbled with 95% / 5%-$O_2$ / $CO_2$ at $37^{\circ}C$, and the pH was maintained at 7.4. Detrusor strips contracted responding to the electrical field stimulation (EFS) by 2 Hz, 20 msec, monophasic square wave of 60 VDC. The initial peak of EFS-Induced contraction was tended to be suppresed by ${\alpha},{\beta}$-methylene-adenosine 5'-triphosphate (mATP), a partial agonist of purinergic receptor, and baclofen, a $GABA_B$ receptor agonist (statistically nonsignificant). The late sustained contraction by EFS was suppressed significantly (p < 0.05) by additions of atropione, a cholinergic muscarinic receptor antagonist and baclofen. The adenosine 5'-triphosphate-induced contraction was completely abolished by mA TP but not by baclofen. In the presence of atropine, the subsequent addition of acetylcholine could not contract the muscle strips: but the addition of acetylcholine in the presence of baclofen evoked a contraction to a remarkable extent. These results suggest that in the condition of present study, the cholinergic innervation may play a more important role than the purinergic one, and baclofen suppresses the contractility of rat detrusor by the stimulation of the $GABA_B$ receptors to inhibit the release of neurotransmitter from the cholinergic nerve ending.

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.249-254
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• 2007

The purpose of the present study was to evaluate the bioequivalence of two baclofen tablets, $Baclan^{TM}$ tablet (Yooyoung Pharm. Co., Ltd., Seoul, Korea, reference drug) and Taepyungyang Baclofen tablet (Pacificpharma Corporation, Seoul, Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty-four healthy male Korean volunteers received three tablets containing baclofen 10 mg in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of baclofen were monitored for over a period of 24 hr after the administration by using an LC-MS/MS. $AUC_t,\;C_{max}\;and\;T_{max}$ were compiled from the plasma concentration-time data. Analysis of variance (ANOVA) test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t\;and\;C_{max}$. The 90% confidence intervals of the $AUC_t$ and the $C_{max}$ for Taepyungyang $Baclofen/Baclan^{TM}$ were $log0.92{\sim}log1.06\;and\;log1.03{\sim}log1.22$, respectively. These values were within the acceptable bioequivalence intervals of $log0.80{\sim}log1.25$. It was concluded that Taepyungyang Baclofen tablet was bioequivalent to $Baclan^{TM}$ tablet, in terms of both rate and extent of absorption.

• Korean Journal of Bronchoesophagology
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• v.5 no.2
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• pp.217-221
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• 1999

Chronic hiccup is a rare occurrence but can be debilitating for the patient. Treatment of choice is seldom reported. A 83-year-old male was admitted our hospital due to chronic hiccup for 3 months. Chest PA X-ray and chest CT showed a lung mass finding in the right lower lobe. After percutaneous transthoracic needle aspiration, squamous cell lung cancer with abscess formation was confirmed. Within three days of initiation of baclofen treatment. stop of hiccup was obtained. We report a baclofen effect for chronic hiccup.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.647-655
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• 1997

The purpose of present study is to investigate the influence of a spinal gamma-aminobutyric acid B($GABA_B$) receptor on a central regulation of blood pressure(BP) and heart rate(HR), and to define its mechanism in the spinal cord. In urethane-anesthetized, d-tubocurarine-paralyzed and artificially ventilated male Sprague-Dawley rats, intrathecal administration of drugs were carried out using injection cannula(33-gauge stainless steel) through the guide cannula(PE 10) which was inserted intrathecally at lower thoracic level through the puncture of a atlantooccipital membrane. Intrathecal injection of an $GABA_B$ receptor agonist, baclofen(30, 60, 100 nmol) decreased both BP and HR dose-dependently. Pretreatment with 8-bromo-cAMP(50 nmol), a cAMP analog, or glipizide(50 nmol), a ATP-sensitive $K^+$ channel blocker, attenuated the depressor and bradycardic effects of baclofen(100 nmol), but not with 8-bromo-cGMP(50 nmol), a cGMP analog. These results suggest that the $GABA_B$ receptor in the spinal cord plays an inhibitory role in central cardiovascular regulation and that this depressor and bradycardic actions are mediated by the decrease of cAMP via the inhibition of adenylate cyclase and the opening of $K^+$ channel.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.284.2-284.2
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• 2003

Using a column-switching technique. highly sensitive and selective semi-micro high-performance liquid chromatographic (HPLC) method has been developed for the determination of baclofen in human plasma. Following precipitation of plasma sample containing baclofen with zinc sulfate-acetonitrile, samples were directly injected on to the system. (omitted)

• Progress in Medical Physics
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• v.9 no.2
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• pp.95-104
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• 1998

The dynamic properties of the 3rd-order neuron of the retina was investigated by using conventional intracellular recording techniques. Experiments were performed in the superfused retina-eyecup preparation of the channel catfish, Ictalurus punctatus. The cornea, iris, lens, and vitreous were removed by absorption with Kimwipe tissue under the dissection microscope thereby exposing the retina in a hemi -eyecup. The electrical signal was amplified by electrometer, viewed on oscilloscope. Regular signals from the cells were recorded on a penwriter and stored by data recorder and computer. Full-field, spot or annular light stimuli were generated on a computer monitor and focused onto the retina. Baclofen hyperpolarized the dark membrane potential, suppressed sustained component and enhanced transient component of the ON-sustained cell with a large transient component, but did not affect the surround antagonism of the cell. Baclofen selectively suppressed responses evoked by moving bar light stimuli on the ON-OFF transient cell. The results suggest that transient cells have directional selectivity in the inner retina. These dynamic properties of amacrine and ganglion cells were modulated by baclofen. Therefore, it is presumed that there is baclofen-induced directional selectivity in ON-OFF transient cells in the catfish retina.

• The Korean Journal of Pain
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• v.23 no.1
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• pp.42-45
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• 2010

Hiccups are an involuntarily powerful spasm of the diaphragm, followed by a sudden inspiration with a closure of the glottis. Hiccups that are caused by gastric distention, spicy foods and neural dysfunction can resolve themselves without any treatment. Some hiccups are associated with certain diseases or they occur postsurgically, and life-restricting intractable hiccups should be treated. The cause of hiccups should be quickly determined so as to administer the proper treatment. Hiccups often remit spontaneously within a short period of time, but they may also occur without remission for a prolonged period in some cases. We report here on a 36-year-old man who suffered with intractable hiccups for 5 years. We administered a single oral dose of baclofen, and then the hiccups disappeared. We conclude that a single dose of baclofen is a good treatment for intractable hiccups.

• The Korean Journal of Pain
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• v.10 no.2
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• pp.246-249
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• 1997

Hiccup is defined as an abrupt involuntary contraction of the diaphragm and intercostal muscles with sudden closure of the glottis 35 msec after onset. The term "intractable" is given to those hiccups with a duration ranging from 24 hours to more than 25 years. Short hiccup bouts are mostly associated with gastric distention or alcohol intake, resolved spontaneously or with simple remedies. In contrast, intractable hiccup is a rare but disabling condition which can induce depression, weight loss and sleep deprivation. Although the pathophysiologic mechanisms of hiccup are still poorly understood, wide variety of pathological conditions such as: brain tumor, abdominal tumor, myocardial infarction, renal failure, abdominal surgery etc., can cause intractable hiccup. A 58-year-old male who had suffered from hepatocellular cancer was consulted from medical department due to intractable hiccup. Initial treatment modalities with administrations of metoclopramide and chlorpromazine and nerve block including phrenic nerve block, cervical epidural block and glossopharyngeal nerve block were not effective. Administration of midazolam and baclofen however achieved desirable effect.

• Journal of Yeungnam Medical Science
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• v.9 no.2
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• pp.382-395
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• 1992

GABA is an inhibitory neurotransmitter in central nervous system and produce sedative, antianxiety and muscle reaxing effects via $GABA_A$ receptor or $GABA_B$ receptor. Recently it is known that GABA is widely distributed throughout peripheral organs and may playa physiological role in certain organ. The vas deferens is innervated by species-difference. These study, therefore, was performed to investigate the mode and the mechanism of action of GABA on the norepiniphrine-, ATP- and electric stimulation-induced contraction of vas deferens of rat. Sprague-Dawley rats were sacrificed by cervical dislocation. The smooth muscle strips were isolated from the prostastic portion and were mounted in the isolated muscle bath. PSS in the bath was aerated with 95/5%-$O_2/CO_2$ at $33^{\circ}C$. Muscle tensions were measured by isometric tension transducer and were recorded by biological recording system. 1. GABA, muscimol, a $GAB_A$ agonist, and baclofen, a $GABA_B$ agonist inhibited the electric field stimulation(EFS, 0.2Hz, 1mSec, 80 V, monophasic square wave)-induced contraction with a rank order of potency of GABA greater than baclofen greater than muscimol. 2. The inhibitory effect of GABA was antagonized by delta aminovaleric acid(DAVA), a $GABA_B$ antagonist, but not by bicuculline, a $GABA_A$ mtagonist. 3. The inhibitory effect of baclofen was antagonized by DAVA, but the effect of muscimol was not antagonized by bicuculline. 4. Exogenous norepinephrine(NE) and ATP contracted muscle strip concentration dependently, but the effect of acetylcholine was negligible : and GABA did not affect the NE-and ATP-induced contractions. 5. GABA, baclofen and muscimol did not affect basal tone, and GABA did not affect the NE-and ATP-induced contractionsm 6. EFS-induced contraction was including 2 distinctable components. The first phasic component was inhibited by beta gamma-methylene ATP(mATP), a desensitizing agent of APT receptor and the second tonic component was reduced by pretreatment of reserpine(3 mg/Kg, IP). 7. GABA inhibited the EFS-induced contraction of reserpinized strips, but not the mATP-treated strips. These results suggest that in the prostatic portion of the rat vas deferens, adrenergic and purinergic neurotransmissions are exist, and GABA inhibits the release of ATP via presynaptic $GABA_B$ receptor on the excitatory neurons.

• The Korean Journal of Pain
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• v.26 no.4
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• pp.336-346
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• 2013

Intrathecal drug delivery is an effective and safe option for the treatment of chronic pathology refractory to conventional pain therapies. Typical intrathecal administered drugs are opioids, baclofen, local anesthetics and adjuvant medications. Although knowledge about mechanisms of action of intrathecal drugs are every day more clear many doubt remain respect the correct location of intrathecal catheter in order to achieve the best therapeutic result. We analyze the factors that can affect drug distribution within the cerebrospinal fluid. Three categories of variables were identified: drug features, cerebrospinal fluid (CSF) dynamics and patients features. First category includes physicochemical properties and pharmacological features of intrathecal administered drugs with special attention to drug lipophilicity. In the second category, the variables in CSF flow, are considered that can modify the drug distribution within the CSF with special attention to the new theories of liquoral circulation. Last category try to explain inter-individual difference in baclofen response with difference that are specific for each patients such as the anatomical area to treat, patient posture or reaction to inflammatory stimulus. We conclude that a comprehensive evaluation of the patients, including imaging techniques to study the anatomy and physiology of intrathecal environment and CSF dynamics, could become essential in the future to the purpose of optimize the clinical outcome of intrathecal therapy.