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PubMed1980

Comparison of multigated radionuclide angiography with ultrasonic sonomicrometry over a wide range of ventricular function in the conscious dog.

This study compared the noninvasive assessment of left ventricular function with radionuclide angiography with that obtained with ultrasonic sonomicrometry. Left ventricular ejection fraction and rate of ventricular ejection (dV/dt) were measured with both techniques over a wide range of ventricular function. Six dogs were prepared with epicardial crystals across the major and minor axes of the left ventricle, paired transmural wall thickness crystals and a left ventricular catheter. The animals were studied while awake after they had recovered from operation. Left ventricular volume was calculated from the ultrasonic sonomicrometric dimension measurements and the equation for a prolate ellipsoid; dV/dt was calculated from the stroke volume and ejection time. Radionuclide angiograms were performed using technetium-99m--labeled red blood cells and an Anger camera with a converging collimator interfaced to a computer programmed for multigated acquisition. A wide range of ventricular function was produced with sequential infusion of isoproterenol, propranolol, phenylephrine and sodium thiamylal. Ejection fraction and dV/dt were measured simultaneously during each intervention using the time-activity curves of the multigated radionuclide angiogram and ultrasonic sonomicrometric dimensions. Regression analyses demonstrated a close correlation between the simultaneous measurements of ejection fraction (r values ranged from 0.95 to 0.99) and dV/dt (r values ranged from 0.87 to 0.99). These data indicate that noninvasive multigated radionuclide angiography accurately assesses changes in ejection fraction and dV/dt over a wide range of ventricular function.

Animals↗
PubMed1984

Effects of inotropic and chronotropic stimuli on acute myocardial ischemic injury. III. Influence of basal heart rate.

The influence of basal heart rate (HR) on the effects of inotropic (dobutamine infusion) and chronotropic (atrial pacing) stimuli during acute myocardial ischemia was assessed by measurement of intramural carbon dioxide partial pressure (PCO2) in open-chest dogs undergoing transient 10-minute left anterior descending coronary artery occlusions. In protocol I, in 5 dogs anesthetized with pentobarbital alone, HR increased from 153 +/- 10 to 182 +/- 7 beats/min between experimental coronary occlusions, but the increase in ischemic zone intramural carbon dioxide tension (delta PmCO2) was not altered by this significant increase in HR. In protocols II to V, dogs were anesthetized with combinations of morphine, thiamylal and pentobarbital and had a basal average HR of 81 beats/min. Atrial pacing in protocol II (13 dogs) increased HR from 76 +/- 21 to 134 +/- 19 beats/min (p less than 0.001); left ventricular (LV) myocardial oxygen consumption (MVO2) rose from 3.9 +/- 1.6 to 4.9 +/- 1.4 ml/min/100 g (p less than 0.05), and delta PmCO2 rose from 42 +/- 14 to 50 +/- 15 mm Hg (p less than 0.01), indicating more severe ischemic injury during the second experimental coronary occlusion. In protocol III, 11 dogs received 20 micrograms/kg/min of dobutamine before the second experimental occlusion, which significantly (p less than 0.02) increased HR, LV dP/dt and MVO2; delta PmCO2 increased from 46 +/- 13 to 63 +/- 18 mm Hg (p less than 0.01). The 7 dogs in protocol IV received 3.9 +/- 1.9 micrograms/kg/min of dobutamine, titrated such that HR was unchanged (84 +/- 10 vs 81 +/- 15 beats/min), but LV dP/dt increased by 92% (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Determination of thiopental in human serum and plasma by high-performance capillary electrophoresis-micellar electrokinetic chromatography.

The quantitation of thiopental in human serum and plasma was investigated using high-performance capillary electrophoresis (HPCE) in a micellar configuration and the results were compared with reversed-phase high-performance liquid chromatography (HPLC). Thiopental and an internal standard (carbamazepine for HPCE and thiamylal for HPLC) were extracted from serum or plasma using pentane and a phosphate buffer (pH 6.4). HPCE analysis took place in a phosphate-borate buffer with 50 mM sodium dodecyl sulphate using an automated instrument and HPLC was performed with a C8 column and a mobile phase of phosphate buffer-acetonitrile (65:35, v/v). HPCE and HPLC data from 66 patient samples compared well based on linear regression analysis. However, estimates obtained with the inclusion of the internal standard were lower than those based on the sample peak only. This example allows the elucidation of the advantages of using HPCE as an assay methodology for the therapeutic monitoring of thiopental and other drugs.

Chromatography↗
PubMed1991

A new model of myocardial infarction in Yucatan minipigs.

Myocardial infarction studies in pigs have been complicated by the use of antiarrhythmic drugs or the high incidence of ventricular fibrillation. We report on a new model of experimental myocardial infarction in thiamylal-anesthetized Yucatan minipigs. These studies were performed in the absence of intravenous antiarrhythmic drugs. No animals required resuscitation during either surgery or reperfusion and only 19% were resuscitated during occlusion. Extensive systemic hemodynamic, regional contractility and coronary blood flow measurements were continuously obtained during left anterior descending coronary artery (LAD) occlusion (45 min) and reperfusion (240 min). Mean arterial blood pressure and left ventricular + dP/dt decreased during occlusion, and both declined further upon reperfusion. Persistent dysfunction (segmental shortening from 24.8 +/- 1.3 to 3.9 +/- 0.9% (p less than 0.001); pre-occlusion and 5 min post-occlusion, respectively) occurred immediately after occlusion in the myocardium perfused by the LAD, while late declines in segmental shortening (19.6 +/- 0.9 to 17.2 +/- 1.2%; pre-occlusion and 240 min post-reperfusion, respectively) were observed in myocardium perfused by the left circumflex coronary artery. While heart rate did not change during occlusion, tachycardia occurred at the onset of reperfusion. Although initial reactive hyperemia following reperfusion was manually inhibited, high LAD blood flow following reperfusion occurred early (0 to 60 min) but returned below pre-occlusion values late (180 to 240 min). The area at risk represented 23.1 +/- 0.9% (n = 34) of the left ventricle and 39.0 +/- 3.2% of this area was infarcted. Therefore, 9.2 +/- 0.9% of the left ventricle was infarcted. These data suggest that myocardical infarction in anesthetized minipigs can be achieved without the aid of intravenous antiarrhythmic drugs and reduced cardioversion. Therefore, this new model can be utilized in the evaluation of therapeutic compounds focused on altering the detrimental consequences of myocardical infarction.

Anesthesia↗
PubMed1989

Complications associated with barbiturate therapy.

Fifty-six patients with elevated intracranial pressure caused by cerebrovascular accident, head injury, etc., were the subjects of this study. They were divided into three groups: low dose barbiturate therapy (15 patients), high dose barbiturate therapy (24 patients), and control group (17 patients). Barbiturate therapy was instituted using thiamylal, and the complications caused by barbiturate therapy were recorded. In the control group, complications occurred in the liver of two patients, but there were no renal or pulmonary complications. Pulmonary, renal, and hepatic complications were common in the barbiturate groups. Complications in the high dose therapy group were significantly more common than in the control group. Opportunistic infections occurred in ten patients, with seven patients having pneumonia. Only one patient, with pneumonia, was seen in the control group. The deaths of three patients were influenced by complications associated with barbiturate therapy, while the single death in the control group was not associated with the complication of barbiturate therapy.

Adolescent↗
PubMed1990

Nonsegmental inhibition of rat dorsal horn neurons by innocuous stimulation.

In rats anesthetized with thiamylal sodium, responses of spinal cord dorsal horn neurons to noxious skin heating of the tail were recorded by extracellular microelectrodes. Inhibition of these responses by innocuous mechanical stimulation (light brushing) of the ipsilateral forelimb was assessed. Short-lasting application (3 min, or less) of light brushing did not inhibit neuronal responses to noxious heating. Long-lasting application (5 min, or more) inhibited responses of these neurons to noxious stimulation. The results indicate that, in the anesthetized rat, remotely applied innocuous cutaneous stimuli can inhibit nociceptive responses of dorsal horn neurons, if applied for a sufficiently long time.

Afferent Pathways↗
PubMed1991

Inhibition of endotoxin-induced monocytic procoagulant activity by n-alcohols and anesthetics.

1. The effect of n-alcohols (methanol and ethanol) and anesthetics (lidocaine, thiopental, methohexital and thiamylal) on procoagulant activity (PCA) in human peripheral-blood monocytes and non-adherent cultured leukemia promonocytic U937 and THP-1 cells was examined herein. 2. Exposure of whole blood to ethanol showed no effect on PCA in human monocytes. However, ethanol dose-dependently inhibited LPS-induced PCA in isolated human monocytes. 3. In THP-1 cells, ethanol had no significant effect on PCA in either non-challenged or LPS-induced status. However, the induction of PCA by LPS was substantially inhibited when cells were pretreated with 1% ethanol (v/v) for 72 hr. 4. In U937 cells, n-alcohols and anesthetics resulted in dose-dependent depressions in PCA. Importantly, the percent reduction in LPS-induced PCA was much more pronounced than that in non-challenged PCA. 5. These data clearly suggest that n-alcohols and anesthetics readily inhibit the LPS-stimulatory action on monocytic PCA.

Anesthetics↗
PubMedDate not supplied

Elderly patients recover more rapidly from desflurane than from isoflurane anesthesia.

STUDY OBJECTIVE: To compare the hemodynamic, emergence, and recovery characteristics of desflurane-nitrous oxide (N2O) anesthesia with those of isoflurane-N2O anesthesia in elderly patients. DESIGN: Randomized study. SETTING: Main operating room of a major U.S. teaching hospital. PATIENTS: Thirty-four ASA physical status II and III patients aged 65 or older undergoing surgical procedures of greater than 1 hour duration. INTERVENTIONS: Group 1 (17 patients) received desflurane in 60% N2O for their surgical procedure. Group 2 (17 patients) received isoflurane in 60% N2O. Thiamylal 2 mg/kg administered intravenously (IV) induced anesthesia, and succinylcholine 1.5 mg/kg i.v. facilitated intubation. Muscle relaxation was maintained with vecuronium. Titration of the anesthetics maintained hemodynamics to within 20% of the patients' preinduction values. MEASUREMENTS AND MAIN RESULTS: Measurement of hemodynamics occurred every 2 minutes prior to skin incision and every 5 minutes thereafter. The times for discontinuation of inhaled anesthetics to eye opening, hand grip on command, and recall of name and date of birth were measured in a standardized fashion for both groups. The time to discharge from the postanesthesia care unit (PACU) was determined by a blinded PACU nurse using standard published criteria. The two groups did not differ with respect to demographics, hemodynamic stability, and times to eye opening (5 +/- 3 minutes for desflurane vs. 8 +/- 4 minutes for isoflurane), hand grip on command (9 +/- 4 minutes vs. 12 +/- 1 minutes), and recall of name and date of birth (13 +/- 8 minutes vs. 12 +/- 7 minutes). The median duration of PACU stay was significantly shorter (p < 0.03) in the desflurane group (80 minutes) compared to the isoflurane group (128 minutes). CONCLUSIONS: Desflurane may benefit elderly patients by providing a more rapid recovery from anesthesia, leading to a shorter PACU stay.

Aged↗
PubMed1995

Comparison of cardiovascular responses to airway management: fiberoptic intubation using a new adapter, laryngeal mask insertion, or conventional laryngoscopic intubation.

STUDY OBJECTIVES: To evaluate the circulatory effects of fiberoptic intubation with a newly developed mask adapter and to compare these effects with those obtained with a conventional laryngoscope and laryngeal mask airway with general anesthesia. DESIGN: Randomized study. SETTING: Operating room at a university hospital. PATIENTS: 30 ASA physical status I adult patients scheduled for minor elective surgery. INTERVENTIONS: A Macintosh laryngoscope was used for intubation in Group L (n = 10), a fiberoptic bronchoscope with newly developed mask adapter was used in Group FI (n = 10), and a laryngeal mask airway was used in Group LMA (n = 10). Anesthesia was induced with thiamylal, fentanyl, and vecuronium. Patients were manually ventilated for 4 minutes with sevoflurane. Then their tracheas were intubated with a laryngoscope or fiberoptic bronchoscope, or a laryngeal mask airway was inserted. MEASUREMENTS AND MAIN RESULTS: Blood pressure (BP) and heart rate (HR) were measured continuously. After intubation, the magnitude of change of both BP and HR was greatest in Group L, next highest in Group FI, and lowest in Group LMA. CONCLUSION: Fiberoptic intubation with general anesthesia using the newly developed mask adapter offers an advantage over the standard laryngoscope for patients in whom pressor response of intubation is potentially hazardous.

Adult↗
PubMed1995

The efficacy of guanfacine in reducing perioperative hemodynamic changes and volatile anesthetic requirement.

STUDY OBJECTIVE: To evaluate the efficacy of guanfacine, an alpha 2-adrenergic agonist, for attenuating hemodynamic changes associated with tracheal intubation or extubation, providing intraoperative hemodynamic stability, and reducing inhalation anesthetic requirement in patients undergoing gynecologic surgery. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Inpatient gynecology at a university hospital. PATIENTS: 45 women (ASA I) undergoing elective abdominal hysterectomy. INTERVENTIONS: Guanfacine and placebo supplementation. Oral guanfacine at 0.5 or 1 mg or a placebo (control) 3 hours before induction of anesthesia. Anesthesia was induced with thiamylal 5 mg/kg and vecuronium 0.2 mg/kg, and maintained with isoflurane and 50% nitrous oxide (N2O) in oxygen. The inspired isoflurane concentration was maintained at 1% during the first 5 minutes following induction of anesthesia and titrated to the concentration required to maintain hemodynamic stability [defined as +/- 10% of systolic blood pressure (SBP)]. The end-tidal concentration of isoflurane was monitored throughout anesthesia. On completion of surgery, N2O and isoflurane were discontinued. Following confirmation of recovery from anesthesia and muscle relaxation, the endotracheal tube was removed. MEASUREMENTS AND MAIN RESULTS: Patients in the control group showed significant increases in SBP and diastolic blood pressure (DBP) and heart rate (HR) associated with tracheal intubation 50 +/- 5, 57 +/- 6.3, and 45 +/- 4.6 (%, mean +/- SEM, p < 0.05 for any variables), respectively. Plasma norepinephrine and epinephrine concentrations increased to 382 +/- 40 pg/ml and 49 +/- 4.2 pg/ml, respectively (p < 0.05 compared with basal values). These changes were attenuated in patients receiving 1 mg of guanfacine (29 +/- 4.2, 33 +/- 4.5, 25 +/- 3.2, 210 +/- 32, and 22 +/- 3.5, respectively (p < 0.05 for any variables compared with placebo group). Higher inspired concentrations of isoflurane (%) were required in the control and 0.5 mg guanfacine-treated groups (1.2 +/- 0.05 and 1.0 +/- 0.04, respectively) than in the 1 mg guanfacine-treated group (0.62 +/- 0.03) for hemodynamic stability (p < 0.05). Coefficient of variation in HR changes during surgery was 17.2, 13.9, and 8.8 in the placebo, guanfacine 0.5 mg, and guanfacine 1 mg treated groups, respectively. Compared with placebo, guanfacine 1 mg reduced the maximum changes (mean +/- SEM) in SBP (7 +/- 1.2 vs. 18 +/- 2.2) and in HR (23 +/- 2.1 vs. 44 +/- 3.6) occurring during tracheal extubation. The incidence of perioperative complications was similar among the three groups. CONCLUSION: Guanfacine 1 mg administered orally proved to be an effective premedicant for providing intraoperative hemodynamic stability, attenuating the increase in BP and HR associated with tracheal intubation and extubation, and reducing anesthetic requirements without increasing the incidence of perioperative complications.

Adult↗
PubMed1996

Propofol permits tracheal intubation but does not affect postoperative myalgias.

STUDY OBJECTIVE: To determine the effect of propofol without succinylcholine on intubating conditions and postoperative myalgias in ambulatory surgical patients undergoing general anesthesia. DESIGN: Prospective, double-blind, randomized study. SETTING: Ambulatory surgery adult patients. PATIENTS: 56 ASA physical status I and II adult patients undergoing general endotracheal anesthesia. INTERVENTIONS: Group 1 patients received thiamylal plus succinylcholine, Group 2 patients received propofol plus succinylcholine; and Group 3 patients received propofol plus saline. All patients received fentanyl, lidocaine, and nitrous oxide plus isoflurane in oxygen. MEASUREMENTS AND MAIN RESULTS: Incidence and severity of fasciculations, tracheal intubating conditions, and myalgias on the first and third postoperative days were measured. Propofol did not affect the incidence or severity of fasciculations following succinylcholine, or the incidence of myalgias. Of patients who received propofol without succinylcholine, intubation was successful in 85%. CONCLUSIONS: Propofol did not affect the incidence or severity of postoperative myalgias following succinylcholine.

Adult↗
PubMed1993

Intrathecal morphine during thoracotomy, Part I: Effect on intraoperative enflurane requirements.

The ability of intrathecal morphine to reduce the anesthetic requirements during thoracotomy was investigated. Twenty-four patients scheduled for thoracic surgery were studied. Anesthesia was induced with thiamylal sodium, 4 mg/kg, fentanyl, 100 micrograms, and 100 mg of succinylcholine. Prior to skin incision, 12 patients received intrathecal injection of 12 micrograms/kg of preservative-free morphine sulfate (ITM), while the remaining 12 patients served as controls. The ITM was given undiluted at the L3-4 or L4-5 level. Anesthesia was maintained solely with enflurane, titrated to keep mean arterial pressure within 15% of the preoperative values. Vecuronium was given as required for relaxation. No additional narcotics were administered. Throughout the procedure, end-tidal (ET) enflurane concentration was recorded at 15-minute intervals from the mass spectrometer (Perkin Elmer). The intraoperative mean ET concentration of enflurane was significantly reduced in the ITM group beginning 1 hour after the injection (1.19 +/- .45% in the control group versus 0.73 +/- 0.08% in the ITM group). The enflurane requirements, expressed as percent end-tidal enflurane/hour, were significantly less in the ITM group for the duration of the procedure (0.8 +/- .17 v 1.08 +/- .22, respectively). In conclusion, when administered prior to skin incision for post-thoracotomy pain control, intrathecal morphine reduces intraoperative enflurane requirements.

Aged↗
PubMed1993

Intrathecal morphine during thoracotomy, Part II: Effect on postoperative meperidine requirements and pulmonary function tests.

The ability of intrathecal morphine (ITM) to reduce post-thoracotomy pain and meperidine requirements was investigated. Thirty adult patients scheduled for thoracic surgery were studied. Following induction with thiamylal sodium and succinylcholine, anesthesia was maintained with 100 micrograms of fentanyl, vecuronium, and enflurane. Prior to skin incision, 16 patients received intrathecal morphine, 12 micrograms/kg, injected at the L3-4 or L4-5 level. The other 14 patients were controls. Postoperatively, patients were evaluated for pain scores and the total doses of meperidine required over 24 hours. The patients in the ITM group required significantly less meperidine compared to the control group (59 +/- 68 v 167 +/- 97 mg, respectively) and had lower pain scores (1.4 +/- 1.1 v 2.4 +/- 0.9 mg, respectively). There were no serious side effects attributable to ITM. It is concluded that ITM is an effective adjunctive treatment for control of post-thoracotomy pain.

Aged↗
PubMed1994

Inhibition of nitric oxide synthesis causes systemic and pulmonary vasoconstriction in isoflurane-anesthetized dogs.

The postulate that the hemodynamic changes produced by isoflurane (1.5%) involve release of nitric oxide (NO) was examined. Fifteen dogs were anesthetized with thiamylal (15 mg/kg) and ventilated with isoflurane and oxygen. Catheters were inserted for measurement of aortic pressure, pulmonary artery pressures, and determination of cardiac output. Left thoracotomy was performed and complete heart block was induced by injection of 37% formaldehyde (0.3 mL) into the atrioventricular node; ventricular rate was fixed at 100 beats/min by external pacing. An apical microtransducer was inserted into the left ventricle (LV) via the apex for measurement of left ventricular pressure (LVP) and its first derivative (dP/dt). Flow probes were mounted on the left circumflex (Cx) and anterior descending (AD) coronary arteries. Measurements were obtained before (control period) and during NO inhibition using IV NG-nitro-L-arginine methyl ester (L-NAME) by a 50 mg/kg bolus plus 1 mg/kg/min. Infusion of L-NAME caused immediate and sustained increases in mean arterial pressure to 145 +/- 3% (P < 0.001), mean pulmonary arterial pressure to 128 +/- 5% (P < 0.001), pulmonary capillary wedge pressure to 144 +/- 8% (P < 0.001), coronary perfusion pressure to 163 +/- 4% (P < 0.001), systemic vascular resistance to 209 +/- 9% (P < 0.001), pulmonary vascular resistance to 142 +/- 12% (P < 0.005), anterior descending flow to 115 +/- 4% (P < 0.005), and circumflex flow to 113 +/- 3% (P < 0.01) of control levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed2005

A case of acute encephalitis with refractory, repetitive partial seizures, presenting autoantibody to glutamate receptor Gluepsilon2.

An 11-year-old male was admitted to our hospital because of high-grade fever, repetitive seizures, and prolonged impairment of consciousness (Glasgow coma scale E1, M5, V1). His seizures were repetitive complex partial seizures that expanded from the unilateral face to the corresponding side of the body. He sometimes developed secondary generalized seizures. While most seizures lasted 1 or 2 min, intractable seizures also frequently (about 5 times/h) occurred. We diagnosed him as encephalitis/encephalopathy, and treated him with artificial respiration, thiamylal sodium, mild hypothermia therapy, steroid pulse therapy, massive gamma-globulin therapy, etc. Afterwards, he had sequelae, such as post-encephalitic epilepsy (same seizures continued to recur), hyperkinesia, impairment of immediate memory, change in character (he became sunny and obstinate), dysgraphia, and mild atrophy of the hippocampus, amygdala, and cerebrum. However, he could still attend a general junior high school. He was diagnosed as acute encephalitis with refractory, repetitive partial seizures (AERRPS). In this case, he was positive for autoantibody to glutamate receptor Gluepsilon2 IgG or IgM in an examination of blood and spinal fluid, and we presumed that this may have influenced his sequelae. In this case, a combination of mild hypothermia therapy, steroid pulse therapy, and massive gamma-globulin therapy was effective.

Autoantibodies↗
PubMed1977

Chronotropic effect of acetylstrophanthidin infusion into the canine sinus nodal artery.

Studies were performed to determine the chronotropic effect of acetylstrophanthidin during constant infusion through cannulation of the sinus nodal artery. Ten mongrel dogs weighing 13.5 to 18 kg were studied under sodium thiamylal anesthesia. Epicardial atrial and ventricular electrograms were recorded. The sinus nodal artery was cannulated and infused for 20 minutes at a rate of 2 cc/min with a solution containing acetylstrophanthidin, 0.5 microng/cc. Mean results for the group of 10 animals were determined. There was a gradual acceleration of the atrial rate of 45 beats/min after 6 to 8 minutes of infusion. The peak atrial rate of 175 beats/min was achieved by 10 to 12 minutes. This tachycardia persisted for 2 to 4 minutes without atrioventricular block or premature beats. By 12 to 14 minutes, there was a gradual slowing of atrial rate followed by bradycardia, sinus pauses and atrial arrest. Sinus nodal arterial infusion of acetylstrophanthidin produces an initial positive chronotropic effect and, if maintained, a depression of atrial rate and, terminally, atrial arrest. The gradual time course of development and decline of the tachycardia suggests that the "paroxysmal" atrial tachycardia caused by digitalis excess is the result of enhanced pacemaker automatically rather than reentry, and thus is not truly paroxysmal.

Animals↗
PubMed1983

Induction by barbiturates of a cytochrome P-450-dependent fatty acid monooxygenase in Bacillus megaterium: relationship between barbiturate structure and inducer activity.

In a recent communication (Narhi, L. and Fulco, A.J. [1982] J. Biol. Chem. 257, 2147-2150) we found that a soluble cytochrome P-450-dependent fatty acid monooxygenase isolated from Bacillus megaterium ATCC 14581 could be induced about 28-fold by phenobarbital. We have now examined 19 barbiturates and found that 13 significantly induce the specific monooxygenase activity. Of these, 11 are more active than phenobarbital and three (secobarbital, thiamylal and methohexital) are more than 30 times as active on a molar basis. The dialkyl barbiturates without exception show an excellent correlation between increasing lipophilicity and increasing potency as inducers as do most of the barbiturates containing an aromatic substituent. Nevertheless, it is apparent that certain structural features involving factors other than lipophilicity are also necessary for induction. Our finding that barbiturates can cause the non-substrate induction of a cytochrome P-450-dependent monooxygenase in a prokaryote represents a unique discovery that may provide a relatively simple model for apparently similar induction systems in higher animals.

Bacillus megaterium↗
PubMed1996

Examination of the afferent fiber responsible for the suppression of jaw-opening reflex in heat, cold, and manual acupuncture stimulation in rats.

The possible afferent fibers that participate in the inhibition of jaw-opening reflex (JOR) were examined using selective conduction blockade by topically applied capsaicin. Blood pressure, heart rate, and rectal temperature were monitored, and bilateral femoral nerves were denervated in thiamylal anesthetized Wistar rats. The sciatic nerves were exposed bilaterally and two cotton balls, one soaked with 1.5% capsaicin and the other with saline, were directly applied to the nerve trunk on the respective sides. We verified the conduction blockade of the compound action potentials A delta and C fibers by 1.5% capsaicin. The evoked activity of the digastric electromyography elicited by electrical stimulation of the tongue (1.5 x T, duration 200 microseconds, interval 2 ms, twin pulse, 0.2 Hz) was monitored. On the saline-treated side, the JOR was gradually inhibited by manual acupuncture stimulation of the ipsilateral hindpaw (80 s), and the effect continued after the cessation of the stimulus. This response was not obtained with the manual acupuncture stimulation on the capsaicin-treated side. Immersion of the hindpaw in hot water (53 degrees C, 40 s) induced a rapid and potent inhibition of the JOR on the saline-treated side, but not on the capsaicin-treated side. Cold water immersion (10 degrees C, 40 s) had no apparent suppressive effect on either side, but it had a rather facilitative effect on the JOR on the saline-treated side. The inhibition of the JOR was elicited by manual acupuncture stimulation of various segmental areas such as the nose, auricle, forepaw, abdomen, hindleg and hindpaw. These results suggest that the capsaicin-sensitive thin afferent fibers (A delta and C afferent fibers) mediated by receptors such as polymodal receptors are activated by manual acupuncture stimulation and that they participate in the peripheral processes that of inhibition of the JOR by diffuse noxious inhibitory controls.

Acupuncture Therapy↗