• Title/Summary/Keyword: $H_2$수용체 차단제

Search Result 22, Processing Time 0.023 seconds

Effects of FK224, a $NK_1$ and $NK_2$ Receptor Antagonist, on Plasma Extravasation of Neurogenic Inflammation in Rat Airways (미주 신경의 전기적 자극으로 유발된 백서의 기도내 혈장 유출에 대한 FK224의 효과)

  • Shim, Jae-Jeong;Lee, Sang-Yeub;Lee, Sang-Hwa;Park, Sang-Myun;Seo, Jeong-Kyung;Cho, Jae-Yun;In, Kwang-Ho;Yoo, Se-Hwa;Kang, Kyung-Ho
    • Tuberculosis and Respiratory Diseases
    • /
    • v.42 no.5
    • /
    • pp.744-751
    • /
    • 1995
  • Background: Asthma is an inflammatory disease because there are many inflammatory changes in the asthmatic airways. Axon reflex mechanisms may be involved in the pathogenesis of asthma. Sensory neuropeptides are involved in this inflammation, which is defined as neurogenic inflammation. Substance p, neurokinin A, and neurokinin B may be main neuropeptides of neurogenic inflammation in airways. These tachykinins act on neurokinin receptors. Three types of neurokinin receptors, such as $NK_1$, $NK_2$, and $NK_3$, are currently recognized, at which substance p, neurokinin A, and neurokinin B may be the most relevant natural agonist of neurogenic inflammation in airways. The receptor subtypes present in several tissues have been characterized on the basis of differential sensitivity to substance p, neurokinin A, and neurokinin B. Plasma extravasation and vasodilation are induced by substance p more potently than by neurokinin A, indicating NK1 receptors on endothelial cells mediate the response. But airway contraction is induced by neurokinin A more potently than by substance P, indicating the $NK_2$ receptors in airway smooth muscles. These receptors are used to evaluate the pathogenesis of brochial asthma. FK224 was identified from the fermentation products of Streptomyces violaceoniger. FK224 is a dual antagonist of both $NK_1$ and $NK_2$ receptors. Purpose: For a study of pathogenesis of bronchial asthma, the effect of FK224 on plasma extravasation induced by vagal NANC electrical stimulation was evaluated in rat airway. Method: Male Sprague-Dawley rats weighing 180~450gm were anesthetized by i.p. injection of urethane. Plasma extravasation was induced by electrical stimulation of cervical vagus NANC nerves with 5Hz, 1mA, and 5V for 2 minutes(NANC2 group) and for sham operation without nerve stimulation(control group). To evaluate the effect of FK224 on plasma extravasation in neurogenic inflammation, FK224(1mg/kg, Fujisawa Pharmaceutical Co., dissolved in dimethylsulphoxide; DMSO, Sigma Co.) was injected 1 min before nerve stimulation(FK224 group). To assess plasma exudation, Evans blue dye(20mg/kg, dissolved in saline) was used as a plasma marker and was injected before nerve stimulation. After removal of intravascular dye, the evans blue dye in the tissue was extracted in formamide($37^{\circ}C$, 24h) and quantified spectrophotometrically by measuring dye absorbance at 629nm wavelength. Tissue dye content was expressed as ng of dye per mg of wet weight tissue. The amount of plasma extravasation was measured on the part of airways in each groups. Results: 1) Vagus nerve(NANC) stimulation significantly increased plasma leakage in trachea, main bronchus, and peripheral bronchus compared with control group, $14.1{\pm}1.6$ to $49.7{\pm}2.5$, $17.5{\pm}2.0$ to $38.7{\pm}2.8$, and $12.7{\pm}2.2$ to $19.1{\pm}1.6ng$ of dye per mg of tissue(mean ${\pm}$ SE), respectively(p<0.05). But there was not significantly changed in lung parenchyma(p>0.05) 2) FK224 had significant inhibitory effect upon vagal nerve stimulation-induced airway plasma leakage in any airway tissues of rat,such as trachea, main bronchus, and peripheral bronchus compared with vagus nerve stimulation group, 49%, 58%, and 70%, respectively(p<0.05). Inhibitory effect of FK224 on airway plasma leakage in neurogenic inflammation was revealed the more significant in peripheral bronchus, but no significant in lung parenchyma. Conclusion: These results suggest that FK224 is a selective NK receptor antagonist which effectively inhibits airway plasma leakage induced by the endogenous neurotransmitters relased by neurogenic inflammation in rat airway. Tachykinin receptor antagonists may be useful in the treatment of brochial asthma.

  • PDF

A Study on the Post-Receptor Mechanism of Adenosine Receptor on Acetylcholine Release in the Rat Hippocampus (흰쥐 해마에서 Acetylcholine 유리에 관여하는 Adenosine Receptor의 Post-Receptor 기전에 관한 연구)

  • Choi, Bong-Kyu;Oh, Jae-Hee
    • The Korean Journal of Pharmacology
    • /
    • v.30 no.3
    • /
    • pp.263-272
    • /
    • 1994
  • Since it was been reported that the depolarization-induced ACh release is inhibited by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus, a large body of experimental data on the post-receptor mechanism of this process has been accumulated. But, the post-receptor mechanism of presynaptic $A_1-adenosine$ receptor on the ACh release has not been clearly elucidated yet. Therefore, it was attempted to clarify the post-receptor mechanisms of the $A_1-adenosine$ receptor-mediated control of ACh release in this study. Slices from rat hippocampus were equilibrated with $^3H-choline$ and the release of the labelled products was evoked by electrical stimulation (3 Hz, 5 $VCm^{-1}$, 2ms, rectangular pulses), and the influence of various agents on the evoked tritium-outflow was investigated. Adenosine, in concentrations ranging from $0.3{\sim}300\;{\mu}M$, decreased the ACh release in a dose-dependent manner, without affecting the basal rate of release. The adenosine effects were significantly inhibited by $DPCPX\;(2\;{\mu}M)$, a selective $A_1-receptor$ antagonist. The responses to N-ethylmaleimide $(10&30{\mu}M)$, a SH-alkylating agent of G-protein, were characterized by increments of the evoked ACh-release and the basal release, and the adenosine effects were completely abolished by NEM pretreatment. PDB $(1{\sim}10\;{\mu}M)$, a specific protein kinase C (PKC) activator, increased, whereas PMB $(0.03{\sim}1\;mg)$, a PKC inhibitor, decreased the evoked ACh-release, and the adenosine effects were not affected by these agents. Nifedipine $(1\;{\mu}M)$, a $Ca^{2+}\;-channel$ blocker of dihydropyridine analogue, significantly inhibited the adenosine effect, but glibenclamide, a $K^+-channel$ blocker, did not. Finally, 8-bromo cyclic AMP $(100\;&\;300{\mu}M)$, a membrane-permeable analogue of cAMP, did not alter the ACh release, but adenosine effects were inhibited by pretreatment with large dose of 8-br-cAMP $(300\;{\mu}M)$. These results indicate that the decrement of the evoked ACh-release by $A_1-adenosine$ receptor is mediated by the G-protein, and nifedipine-sensitive $Ca^{2+}-channel$ and adenylate cyclase system are coupled partly to this effect, and that protein kinase C and glibenclamide-sensitive $K{^+}-channel$ are not involved in this process.

  • PDF

Upper Gastrointestinal Bleeding in Full-Term Infants (만삭아에서 발생한 상부위장관 출혈에 대한 임상적 고찰)

  • Choi, Hyon Ju;Kim, Jae Seon;Yoon, Hye Sun;Bae, Sun Hwan
    • Pediatric Gastroenterology, Hepatology & Nutrition
    • /
    • v.8 no.2
    • /
    • pp.164-171
    • /
    • 2005
  • Purpose: The aim of this study was to evaluate the clinical characteristics, endoscopic findings and risk factors related to the upper gastrointestinal bleeding (UGIB) seen in full-term infants. Methods: A clinical analysis for 9 cases with UGIB confirmed by endoscopy was carried out retrospectively. Patients were admitted to the Department of Pediatrics, Eulji Hospital, from January to December 2003. Results: UGIB from gastric or duodenal mucosal lesions has been seen in 0.13% in newborns infants. All patients were full-term AGA neonates without asphyxic findings at birth. Hematemesis, melena or recurrent vomiting developed within $4.4{\pm}3.8days$ after birth. Vital sign and laboratory test was normal on admission. Endoscopic findings showed hemorrhagic gastritis in 6 cases and peptic ulcers in 3 cases. All patients were successfully managed by medical treatment for $18.6{\pm}5.0days$. On treatment, clinical symptoms improved within $0.9{\pm}0.3days$. Follow-up endoscopy was not performed because there was no recurrence of symptoms in all patients. Case mothers had no history of gastritis, ulcer or anti-ulcer medications before and during pregnancy. Conclusion: If the healthy full-term infants express UGIB within a few days after birth, it is necessary to take careful history of family, mother and delivery process and to practice endoscopy for mucosal lesions of the patients. A follow-up endoscopy dose not seem to be necessary if the infant is clinically well.

  • PDF

Medical Treatment of Laryngopharyngeal Reflux (인후두역류의 약물치료)

  • Chu, Hyung-Ro
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
    • /
    • v.18 no.2
    • /
    • pp.108-112
    • /
    • 2007
  • Otolaryngological manifestations of acid reflux include a wide range of pharyngeal and laryngeal symptoms ; and the constellation of symptoms has been called laryngopharyngeal reflux (LPR). In the absence of definite diagnostic criteria, LPR disease remains a subjective entity. A diagnosis of LPR is usually based on response of symptoms to empirical treatment. Investigative modalities such as pH monitoring and, more recently, impedance studies are generally reserved for treatment failures. LPR usually requires more aggressive and prolonged treatment to achieve regression of both symptoms and laryngeal findings. The suppression of gastric acid and secretion with anti-secretary agents has been the mainstay of medical treatment for patients with acid-related disorders. The suppression of gastric acid secretion achieved with Hz-receptor antagonist $(H_2RA)$ has proved suboptimal for relief of reflux symptoms. The rapid development of tolerance and rebound acid hypersecretion after the with-drawal of $H_2RA$ limit their clinical use. Proton pump inhibitors (PPI) have been proved to be very effective for suppressing intragastric acidity, but the optimal dose and duration is unknown. Current evidence indicates that pharmacologic intervention should include, at a minimum, a 3 month trial of twice daily PPI. Symptoms of LPR improve over 2 months of therapy. The physical findings of LPR resolve more slowly than the symptoms and this continues through out at least 6 months of treatment. For most patients with LPR, twice daily dosing with a PPI is usually recommended for an initial treatment for a period of no less than 6 months treatment, and lifetime treatment may be required.

  • PDF

Changes of Glutamate and Polyamine Levels of Hippocampal Microdialysates in Response to Occlusion of Both Carotid Arteries in Mongolian Gerbils (뇌허혈 손상에 있어서 해마-세포외액내 Glutamate와 Polyamine 농도의 변동에 관한 연구)

  • Shin, Kyung-Ho;Kim, Hyung-Gun;Choi, Sang-Hyun;Cho, So-Hyun;Chun, Yeon-Sook;Chun, Boe-Gwun
    • The Korean Journal of Pharmacology
    • /
    • v.30 no.3
    • /
    • pp.273-289
    • /
    • 1994
  • Reversible brain ischemia was produced by occluding both common carotid arteries for 5 min, and the effects of aminoguanidine (AG), $DL-{\alpha}-difluoromethylornithine$ (DFMO), MK-801, and nimodipine (NM) on the ischemia induced changes of the polyamine, glutamate and acetylcholine levels in the hippocampus CA1 subfield and the specific $[^3H]\;MK-801$ binding to the hippocampus synaptosomal membranes were studied with a histological reference of the cresyl violet stained hippocampus. The basal putrescine level $(PT:\;74.4{\pm}8.8\;nM)$ showed a rapid increase (up to 1.7 fold) for 5 min of ischemia, remained significantly increased for 6 h, and then resumed the further increase to amount gradually up to about 3 fold 96 h after recirculation. However, the level of spermidine was little changed, and the spermine level showed a transient increase during ischemia followed by a sustained decrease to about 40% of the preischemic level after recirculation. The increase of PT level induced by brain ischemia was enhanced with AG or MK-801, but it was reduced by DFMO or NM. The basal glutamate level $(GT:\;0.90{\pm}0.l4\;{\mu}M)$ rapidly increased to a peak level of $8.19{\pm}1.14\;{\mu}M$ within 5 min after onset of the ischemia and then decreased to the preischemic level in about 25 min after recirculation. And NM reduced the ischemia induced increase of GT level by about 25%, but AG, DFMO and MK-801 did not affect the GT increase. The basal acetylcholine level $(ACh:\;118.0{\pm}10.5\;{\mu}M)$ did little change during/after brain ischemia and was little affected by AG or NM. But DFMO and MK-801, respectively, produced the moderate decrease of ACh level. The specific $[^3H]\;MK-801$ binding to the hippocampus synaptosomal membrane was little affected by brain ischemia for 5 min. The control value (78.9 fmole/mg protein) was moderately decreased by AG and MK-801, respectively but was little changed by DFMO or NM. The microscopic findings of the brains extirpated on day 7 after ischemia showed severe neuronal damage of the hippocampus, particularly CA1 subfield. NM and AG moderately attenuated the delayed neuronal damage, and DFMO, on the contrary, aggravated the ischemia induced damage. However, MK-801 did not protect the hippocampus from ischemic damage. These results suggest that unlike to the mode of anti-ischemic action of NM, AG might protect the hippocampus from ischemic injury as being negatively regulatory on the N-methyl-D-aspartate (NMDA) receptor function in the hippocampus.

  • PDF

Effect of $K^+-channel$ Blockers on the $A_1-adenosine$ Receptor-Coupled Regulation of Electrically-Evoked Norepinephrine Release in the Rat Hippocampus (흰쥐 해마에서 Norepinephrine 유리를 조절하는 $A_1-adenosine$ 수용체의 역할에 미치는 $K^+$ 통로 차단제의 영향)

  • Choi, Bong-Kyu;Kim, Sang-Hoon
    • The Korean Journal of Pharmacology
    • /
    • v.32 no.3
    • /
    • pp.301-309
    • /
    • 1996
  • Since it has been reported that the depolarization-induced NE release is inhibited by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus, a large body of experimental data on the post-receptor mechanism of this process has been accumulated. But, the post-receptor mechanism of presynaptic $A_1-adenosine$ receptor on the NE release has not been clearly elucidated yet. Therefore, it was attempted to clarify the participation of $K^+-channel$ in the post-receptor mechanisms of the $A_1-adenosine$ receptor-mediated control of NE release in this study. Slices from rat hippocampus were equilibrated with $^3H-norepinephrine$ and the release of the labelled products was evoked by electrical stimulation (3 Hz, 5 $VCm^{-1}$, 2 ms, rectangular pulses), and the influence of various agents on the evoked tritium-outflow was investigated. Adenosine, in concentrations ranging from $1{\sim}30\;{\mu}M$, decreased the NE release in a dose-dependent manner, without affecting the basal rate of release. 4AP $(1{\sim}30{\mu}M)$, a specific A-type $K^+-channel$ blocker, increased the evoked NE release in a dose-related fashion, and the basal rate of release is increased by 10 and $30{\mu}M$. TEA $(1{\sim}10{\mu}\;M)$, a nonspecific $K^+-channel$ blocker, increased the evoked NE release in a dose-dependent manner without affecting basal release. The adenosine effects were significantly inhibites by 3 ${\mu}M$ 4AP and 10 mM TEA treatment. 4AP $(30{\mu}M)-$ and TEA (10 mM)-induced increments of evoked NE release were completely abolished in $Ca^{++} free, but these were recoverd in low $Ca^{++} medium. And the effects of $K^+-channel$ blockers in low $Ca^{++} medium were inhibites and abolishes by $Mg^{++} (4 mM) adding and TTX $(0.3{\mu}M)$ adding medium, respectively. These results suggest that the decrement of the evoked NE-release by $A_1-adenosine$ receptor is mediated by 4AP and TEA sensitive $K^+-channel$.

  • PDF

Interaction of Forskolin with the Effect of $N^6-Cyclopentyladenosine$ on $[^3H]-Acetylcholine$ Release in Rat Hippocampus (흰쥐 해마에서 Acetylcholine 유리에 미치는 $N^6-Cyclopentyladenosine$ 및 Forskolin의 영향)

  • Choi, Bong-Kyu;Park, Hie-Man;Kang, Yeon-Wook;Kook, Young-Johng
    • The Korean Journal of Pharmacology
    • /
    • v.28 no.2
    • /
    • pp.129-136
    • /
    • 1992
  • As it has been reported that the depolarization-induced acetylcholine (ACh) release is modulated by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus and various lines of evidence indicate the involvement of adenylate cyclase system in $A_1-adenosine$ post-receptor mechanism in hippocampus, it was attempted to delineate the role of adenylate cyclase system in the $A_1-receptor-mediated$ control of ACh release in this study. Slices from rat hippocampus were incubated with $[^3H]-choline$ and the release of the labelled products was evoked by electrical stimulation $(3\;Hz,\;5\;Vcm^{-1},\;2\;ms,\;rectangular\;pulses)$, and the influence of various agents on the evoked tritium-outflow was investigated. $N^6-cyclopentyladenosine$ (CPA), a specific $A_1-adenosine$ receptor agonist, in concentrations ranging from 0.1 to $10\;{\mu}M$, decreased the $[^3H]-ACh$ release in a dose-dependent manner without the changes of basal rate of release. 8-cyclopentyl-1,3-dipropylxanthine $(DPCPX,\;1{\sim}10\;{\mu}M)$, a selective $A_1-receptor$ antagonist, increased the $[^3H]-ACh$ release in a dose-related fashion with slight increase of basal tritium-release. And the CPA effects were significantly inhibited by DPCPX $(2\;{\mu}M)$ pretreatment and the dose-response curve produced by CPA was shifted to the right. The responses to N-ethylmaleimide $(NEM,\;10\;&\;30\;{\mu}M)$, a SH-alkylating agent of G-protein, were characterized by increments of the evoked ACh-release and the basal release, and the CPA effect were completely abolished by NEM pretreatment. Forskolin, a specific adenylate cyclase activator, in concentrations ranging from 0.3 to $10\;{\mu}M$, increased the evoked ACh-release in a dose-dependent manner and the CPA effects were inhibited by forskolin. These results indicate that the $A_1-adenosine$ heteroreceptor plays an important role in ACh-release via nucleotide-binding protein Gi in the rat hippocampus and that the adenylate cyclase system might be participated in this process.

  • PDF

The clinical effects of Rabeprazole sodium (Pariet$\circledR$) in the treatment of Laryngopharyngeal Reflux (인후두역류질환 ( Laryngopharyngeal Reflux Disease. LPRD )에서 Rabeprazole Sodium (Pariet$\circledR$)의 임상효과)

  • 최홍식;김한수;최현승
    • Proceedings of the KOR-BRONCHOESO Conference
    • /
    • 2002.12a
    • /
    • pp.9-9
    • /
    • 2002
  • 이비인후과 영역에 있어서 위산 역류에 의한 질환의 진단은 쉽지 않고 분명하지 않은 점이 많지만, 병변의 영향은 광범위하며, 실제로 역류에 의한 증상을 가지고 내원하는 환자도 증가하는 추세이다. 인후두역류질환의 치료는 크게 생활습관의 변경, 약물복용, 항역류수술로 나눌 수 있으며, 사용약제는 크게 두 부류로 나누는데, 제산제, H2 수용체 차단제, PPI(Proton Pump Inhibitor) 제제와 같은 산억제 약물군과 Prokinetic 약물군이다. Rabeprazole sodium(Pariet(R))은 PPI 제제에 해당하는 약제로 기존의 omeprazole, lansoprazole, pantoprazole과는 달리 대사 과정 중 CYP2C19에 대한 의존도가 낮아, 개체 간 차이가 적고 빠르고 일정하게 산분비 억제 효과를 나타내는 것으로 알려져 있은 약물이다. 2001년 5월부터 2002년 4월까지 32개 병원에서 Pariet(R) 를 복용한 2166명의 환자를 대상으로 분석하였다. 복용기간에 따라 4군(1군;1-14일, 2군;15-28일, 3군;29-56일, 4군:57일 이상)으로 나누었으며, 8가지 증상(Heart burn, Regurgitation, Chronic cough, Hoarseness, Globus sensation, Chronic throat clearing, Sore throat, Dysphagia)에 대한 호전 여부 및 후두내시경상 개선 정도, 의사에 의한 유용도 평가, 부작용 발생 여부에 대해 연구하였다. 증상개선율 50%이상을 치료 반응군으로 했을때 전체 2166명중 1627명(75.1%)에서 증상의 호전을 보았으며, 이는 복용기간이 길수록 증가하였다. 후두 내시경상 개선 정도는 현저한 개선이 32.9%, 중등도 개선이 38.7%로 대부분 환자에서 객관적인 병변의 호전을 보였으며, 유용도 평가에서는 매우 유용이 37.6%, 유용이 50.3%로 치료효과에 대한 만족도도 높은 것을 알수 있었다. PPI 제제의 부작용으로 보고되고 있는 두통, 오심, 설사, 복통. 변비, 어지럼증. 피곤 중. 소수의 환자가 두통을 호소하였으나, 그다지 심각한 정도는 아니었다. 인후두역류증 치료제로서 Pariet(R) 는 비교적 안전하고 효과가 높은 약물임이 임상 연구 결과 밝혀졌기에 보고하는 바이다.

  • PDF

Influence of Adenosine and Magnesium on Acetylcholine Release in the Rat Hippocampus (흰쥐 해마에서 Acetylcholine 유리에 미치는 Adenosine 및 Magnesium의 영향)

  • Choi, Bong-Kyu;Yoon, Young-Bok
    • The Korean Journal of Pharmacology
    • /
    • v.29 no.2
    • /
    • pp.175-182
    • /
    • 1993
  • As it has been reported that the depolarization-induced ACh release is modulated by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus and various lines of evidence indicate the adenosine effect is magnesium dependent, the present study was undertaken to delineate the role of endogenus adenosine as a modulator of hippocampal acetylcholine release in this study. Slices from the rat hippocampus were equilibrated with $[^3H]-choline$ and the release of the labelled product, $[^3H]-ACh$, was evoked by electrical stimulation(3Hz, $5\;V\;cm^{-1},$ 2ms, rectangular pulses), and the influence of various agents on the evoked tritium outflow was investigated. Adenosine, in concentrations ranging from $0.3\;to\;100\;{\mu}M$, decreased the $[^3H]-ACh$ release in a dose-dependent manner without changing the basal rate of release. $DPCPX(1{\sim}10{\mu}M)$, a selective $A_1-receptor$ antagonist, increased the $[^3H]-ACh$ release in a dose-related fashion with slight increase of basal tritium release. And the effects of adenosine were significantly inhibited by $DPCPX(2{\mu}M)$ treatment. CPCA, a specific $A_2-agonist$, in concentration ranging from $0.3\;to\;30\;{\mu}M$ decreased evoked tritium outflow with increase of basal rate of tritium release, and these effects were also abolished by $DPCPX(2{\mu}M)$ pretreatment. But, $CGS(0.1{\sim}10{\mu}M)$, a recently introduced potent $A_2-agonist$, did not alter the evoked tritium outflow. When the magnesium concentration of the medium was reduced to 0 mM, there was no change in evoked ACh release by adenosine. In contrast, increasing the magnesium concentration to 4 mM, the inhibitory effects of adenosine were significantly potentiated. These results indicate that $A_1-adenosine$ heteroreceptor is involved in ACh-release in the rat hippocampus and the inhibitory effects of adenosine mediated by $A_1-receptor$ is magnesium-dependent.

  • PDF

Effects of Some Metabolic Inhibitors on Phototactic Movement in Cyanobacterium Synechosystis sp. PCC 6803 PTX (람세균 Synechocystis sp. PCC 6803 PTX의 주광성 운동에 미치는 몇가지 대사 억제제의 효과)

  • 박영총
    • Journal of Plant Biology
    • /
    • v.38 no.1
    • /
    • pp.87-93
    • /
    • 1995
  • For understanding physiological nature of phototaxis in Synechocystis sp. PCC 6803 PTX(S. 6803 PTX), we examined the effects of some metabolic inhibitors and cation ionophore on the phototactic movement. In the presence of DCMU, which blocks the photosynthetic electron transport just after photosystem II acceptor, there was no inhibitory effect on the phototaxis up to $100\;\mu\textrm{M}$. Instead, the respiratory electron chain inhibitor such as sodium azide dramatically impaired the phototaxis in S. 6803 PTX. These observations indicate that the phototaxis is linked not to photo-phosphorylation, but to respiratory phosphorylation. When the cells were treated with un couplers such as CCCP or DNP, which dissipate the electrochemical gradient of proton($\Delta\mu_{H}+$) across the cytoplasmic membrane, these chemicals did not affect phototaxis. In contrast, when cells were treated with DCCD or NBD which deprive cells of A TP but leave $\Delta\mu_{H}+$ intact across the membrane, the phototactic movement was severly reduced. These results imply that ATP production, not proton motive force, is involved in the phototactic movement in this organism as a driving motive force. The application of specific calcium ionophore A23187 strongly impaired positive phototaxis. Calcium fluxes should be engaged in the sensory trans-duction of phototactic orientation. Finally, when ethionine was supplimented to culture media, the photomovement of this organism was inhibited. This implies that methylation/demethylation mechanism controls the process of phototaxis in S. 6803 PTX like chemotaxis in E. coli and Salmonella typhimurium.murium.

  • PDF