The present experiment was designed to investigate renal function in conscious rabbits. Pentobarbital caused some reduction of urinary volume and hemohynamics, but the changes were not significant. UnaV, UkV, UclV were not changed by pentobarbital in dose of 3.0~9.0mg/kg i.v.. Urinary flow snd UclV were not changed by pentothal sodium, 5.0mg/kg i.v., but the UnaV and UclV increased from 30.61 to 66.19 uEq/min, from 28.29 to 62.91 uEq/min respectively, after pentothal sodium. There was no change in urinary potassium secretion after pentothal sodium. Left renal arterial infusion of pentothal sodium caused small changes in GFR, and clear increments of UnaV and UclV localized in that kidney in the urethane anesthetized rabbit. Natriuretic and chloruretic effect of pentothal sodium were not seen in mannitol diuresis. These data suggest that 1) the effects of pentobarbital and pentothal may not be the sam in conscious rabbit renal function, 2) natriuretic and chloruetic effect by pentothal may be caused by direct inhibition of sodium reabsorption in the distal nephron in the rabbit.
Diuresis ; Kidney ; Mannitol ; Nephrons ; Pentobarbital ; Potassium ; Rabbits* ; Sodium ; Thiopental ; Urethane

Fusion loss or anomaly of eye muscle and its nerve is a cause of strabismus. This induces adaptation of vergence and muscle length, the mechanisms of which are normally responsible for long-term maintenance of ocular alignment and orthophorization. To determine variability of muscle length adaptation according to age, we divided white rabbits into three groups: Group I(less than 8 weeks of age and 15000gm of body weight), Group II(10~14 weeks and 1500~2000gm), GroupIII(more than 16 weeks and 2500gm). Under local anesthesia with intravenous pentobarbital sodium, the right eyeball was fixed in exotropic position by suturing through the periosteum of the lateral canthal region with 5-o polypropylene. The muscles of left eye were not operated and served as a control. We examined electron microscopically the changes in sarcomere of the experimental right medial rectus(RMR) and right lateral rectus(RLR) after sacrificing four rabbits of each group at 1, 2 and 4 weeks, respectively. Regardless of age, when the muscle(RLR) was immobilized in the lengthened position, sarcomeres were added on and its length decreased, and when the muscle(RMR) was immobilized in the shortened position, sarcomeres were lost and its length increased. In conclusion, the study revealed that experimental extraocular muscle of rabbit is adapted in the direction to produce maximal power of its muscle and maintain ocular alignment constantly.
Anesthesia, Local ; Exotropia* ; Muscles ; Pentobarbital ; Periosteum ; Polypropylenes ; Rabbits ; Sarcomeres ; Strabismus

BACKGROUND: Etomidate is short-acting non-barbiturate intravenous anesthetic with minimal cardiovascular depression. As a small change in venous capacitance significantly alters venous return and thus cardiac output, it is important to know the effects of intravenous anesthetics on venous capacitance. The purpose of this study was to examine the effect of etomidate or pentobarbital (control agent) on venous capacitance. METHOD: All twenty rats (etomidate group: 10, pentobarbital group: 10), weighing 350-450 gram, were anesthetized with pentobarbital 50 mg/kg given intraperitoneally for surgical preparation. Mean arterial pressure (MAP), heart rate (HR), and mean circulatory filling pressure (MCFP) were measured in the awake state(recovered from pentobarbital anesthesia for surgical preparation) as well as during anesthesia with etomidate or pentobarbital. Venous capacitance was assessed before and during anesthesia with etomidate or pentobarbital by measuring MCFP. MCFP was measured during a brief period of circulatory arrest produced by inflating a balloon inserted in right atrium. RESULTS: As compared with MCFP in the corresponding awake state, MCFP was not significantly altered by etomidate but significantly decreased by pentobarbital. As compared with MAP in the corresponding awake state, MAP was not significantly altered by etomidate but significantly decreased by pentobarbital. CONCLUSION: The results suggest that unaltered venous capacitance by etomidate may contribute to a maintained MAP but increased venous capacitance by pentobarbital decrease in MAP of the normovolemic rat.
Anesthesia ; Anesthetics, Intravenous ; Animals ; Arterial Pressure ; Cardiac Output ; Depression ; Etomidate* ; Heart Atria ; Heart Rate ; Pentobarbital ; Rats*

Effect of partial ligation of the abdominal aorta on the glomerular filtration rate (inulin clearance) was observed in 17 male rabbits. Abdominal aorta was ligated to one-half of its original lumen at the level just above branching of the right renal artery under nembutal anesthesia. Seventeen rabbits were observed 30 minutes before the partial ligation, 30 minutes and 90 minutes after the partial ligation. The following results were obtained. 1. Inulin clearance observed 30 minutes before ligation was 1.02+/-0.90 ml/min (Mean+/-S. D.) or 0.52+/-0.46 ml/min/kg in average. 2. Inulin clearance observed 30 minutes after ligation was decreased markedly to 0.46+/-0.58ml/min or 0.23+/-0.29 ml/min/kg in average. 3. Inulin clearance observed 90 minutes after ligation was decreased-slightly to 0.77+/-0.79ml/min or 0.40+/-0.38ml/min/kg in average, suggesting that its findings were occurred by autoregulatory process of the kidney.
Anesthesia ; Aorta, Abdominal* ; Glomerular Filtration Rate* ; Humans ; Inulin ; Kidney ; Ligation* ; Male ; Pentobarbital ; Rabbits ; Renal Artery

The AV node is a structure in the atrial septum at the atrioventricular junction. The atrial septum is important for various types of supravenricular arrgythmia especially for AV node reentrant tachycardia. In this study, it was aimed to understand the electrical propagation in the atrium and the atrial septum, as well as the effects of perinodal cryosurgery. Eleven mongrel dogs weighing between 26.0kg and 34.5kg were divided into control(d dogs) and cryosurgery(6 dogs) group. The animals were anesthetized with pentobarbital sodium(30 mg/kg) and under a normothermic total cardiopulmonary bypass, endocardial template electrodes(left atrium ; 124, right atrium; 128 bipolar electrodes) were placed into the both atria. The endocardial electrocal activation was recorded using a 256 channel computerized mapping system during normal sinus rhythm, atrial pacing, and ventricular pacing. For the cryosurgery group, the endocardial electrical activation was recorded after eight weeks of discrete perinodal cryosurgery. The results are as followings : 1) The electrical propagation from the SA node to the AV node occurred mainly through thick muscle band of the crista terminalis of the right atrium and anterior limbus fossa ovalis. 2) Electrophysiologically, the atrial septum appeared to be 2 layers. 3) During ventricular pacing, the center of the Koch triangle was the first to respond to activation. When the atrial septum of the AV nodal area was activated, the electrical activations propagated asymmetrically and the activity of the left atrium was propagated through the Bachmann's bundle. The left atrial side of the atrial septum was activated 10-15 msec later than the right side during ventricular pacing. 4) The cryosurgery did not change any significant difference in the AH, HV, AV node effective refractory period and AV node Wenckebach period. However, the ventriculo-atrial conduction was blocked in 50% of the animals. 5) In cryosurgery group, the electrical propagation from the SA nodal area to both atrial was similar to the control group except along side the vertical right atrial incision site. 6) The endocardial activation map in the cryosurgery group showed that the activation was spread out from the lateral atrial tissue outside of the cryolesions. The left atrial side of the atrial septum was was activated 6-19 msec later than the right atrial side. In conclusion, electrophysiologically the atrial septum appears to be composed of 2 layers and there is no direct electrical propagation between the AV node and the left atrial side of the atrial septum. The cryosurgery did not influence the electrial activation sequence from the SA node to the AV node except the site of cryolesion.
Animals ; Atrial Septum* ; Atrioventricular Node ; Cardiopulmonary Bypass ; Cryosurgery* ; Dogs ; Heart Atria ; Pentobarbital ; Tachycardia

OBJECTIVETo establish a pig model of chronic external counterpulsation.

METHODSTwelve pigs were anaesthetized with sodium pentobarbital (< or =30 mg/kg.b.w.) and 846 mixture (< or =0.1 ml/kg.b.w.) and counterpulsed in a lateral position for 2 h every two days (totally 36 h) with 0.025 to 0.04 MPa/cm(2) pressure.

RESULTSExternal counterpulsation was successfully completed in all the animals. Combined administration of sodium pentobarbital and 846 mixture resulted in good anesthetic effect with reduced anesthetic dosage and minimal side effect on the viscera (the liver, kidney and heart, etc).

CONCLUSIONThe pig model of chronic external counterpulsation has been successfully established. Combined use of sodium pentobarbital and 846 mixture is recommended for chronic external counterpulsation.

Anesthesia, General ; methods ; Animals ; Animals, Newborn ; Assisted Circulation ; Counterpulsation ; methods ; Models, Animal ; Pentobarbital ; administration & dosage ; Swine

PURPOSE: Cyanotic congenital heart diseases patients are in a state of hypoxia since birth. In general, hypoxia delays atrioventricular conduction. The atrioventricular node in such a hypoxic condition would have a different function, and some possibility for arrhythmia. The authors studied atrioventricular nodal function during hypoxia to elucidate the relationship between hypoxia and arrhythmia, including atrioventricular node in terms of cardiac tissue level. METHODS: After extraction of an adult rabbit heart under pentobarbital anesthesia, the heart was retrogradely perfused through the aorta with graded hypoxic Krebs' solution(100, 70, and 50% oxygen). The intracardiac electrocardiograms were obtained by a custom-made programmed stimulation at basic cyde length 40ms antegradely and retrogradely. All the data was analysed at His-electrogram and conduction time. Refractory periods and Wenckebach cycling length were determined. RESULTS: During antegrade conduction, the fast AV nodal conduction was prolonged and the slow conduction shortened, resulting in decreased compliance of the AV nodal conduction with graded hypoxia. The His-Purkinje system also showed a similar result. Among the refractory periods, only the AV nodal effective refractory period was prolonged with hypoxia. Wenckebach cycle length was sensitive to hypoxia, especially for retrograde conduction. CONCLUSION: Because the AV conduction during hypoxia was characterized by decreased AV conduction compliance, prolonged AV nodal effective refractory period, and sensitive Wenckebach cyding length, hypoxia would not seem to be a special risk for arrhythmia, including AV node.
Adult ; Anesthesia ; Anoxia* ; Aorta ; Arrhythmias, Cardiac ; Atrioventricular Node ; Compliance ; Electrocardiography ; Heart Diseases ; Heart* ; Humans ; Parturition ; Pentobarbital

The effects of oxygenation of differential independent lung ventilation using HFJV (High Frequency Jet Ventilation) and CPAP (Continuous Positive Airway Pressure) on PaO2 and Qs/Qt were studied during one lung anesthesia in 11 mongrel dogs in left semilateral position with pentobarbital anesthesia. The dogs were divided into two groups. In group A(N = 7), following the conventional two lung ventilation, one lung ventilation, HFJV, one lung ventilation, cpap 5 cmH2O, and CPAP 10 cmH20 were applied sequentially. In group B(N =4), following the conventional two lung ventilation the above applications were reversed. In group A PaO2 revealed a similar increase among a two lung ventilation, CPAP 5 cmH2O, CPAP 10 cmH2O and HFJV. Intrapulmonary shunt showed the similar decrease among two lung ventilation, HFJV and CPAP 10cmH2O, but CPAP 5 cmH2O was higher than CPAP 10cmH2O. Although there were no statistically significant differences in PaO2 and shunt among each step in group B, HFJV showed a greate increase in PaO2, and shunt than one lung ventilation, CPAP 5 cmH 20) 20, and CPAP 10 cmH2O. In conclusion, HFJV proved to be more effective than CPAP 5 cmH2O in increasing PaO2 and decreasing shunt in differential independent lung ventilation. Both CPAP and JFJV should be applied in the deflation phase of the nondependent lung to cause an effective increase in PaO2. HFFV proved to be more effective than CPAP in recruiting the small airway closure.
Anesthesia ; Animals ; Continuous Positive Airway Pressure ; Dogs ; Lung* ; One-Lung Ventilation ; Oxygen ; Pentobarbital ; Ventilation*

A study has been made of efferent single fibers in the cat whose axon is projected to the cardiac branches of the right vagus. The main objective of this experiment was to replicate some of the mechanisms involving vagal efferent discharges and to observe the effect of somatic stimulation, pain and coldness, on the discharges. Electrical activities of a single of a single fiber were recorded on the central segments of small cut strands separated from the right cervical vagus under the pentobarbital sodium anesthesia. The fiber was considered to be cardio-inhibitory in function because of the activity in inverse effect on the heart rate in almost all conditions. Pain and cold stimulation of skin reflexly excited these fibers, as did stimulation of baroreceptor in the carotid sinus. Response to the somatic stimulation applied on the skin, by the increase of impulse frequency, amplitude, discharge duration and pulse rate of electrical discharges were observed. The auther observed that efferent fibers in the cutaneous nerve excited the cardiac efferent vagal fibers in response to reflex stimulation.
Anesthesia ; Animals ; Axons ; Carotid Sinus ; Cats ; Heart Rate ; Nerve Fibers, Myelinated ; Pentobarbital ; Pressoreceptors ; Reflex ; Skin

PURPOSE: To evaluate the effects of DMSO on the iris muscle contractility and to compare DMSO with other detergents(ethanol and triton-x 100). METHODS: After anesthesizing rats with an intraperitoneal injection of pentobarbital sodium, each animal was fixed under microscope. The pupil response to the drugs was examined by CCD camera and the video edge motion detector was used for measurement of alteration of the pupil size. The pupil response to the drugs was recorded by MacLab chart(version 3.6/s). RESULTS: Miosis induced by DMSO was initiated after 5 minutes, peaked at around 30 minutes and maintained until 3 hours after instillation. Miotic effect of DMSO was in a dose dependent manner ranging 0.01%-10% and was not reversed after washout. All detergents used in the present experiment induced miosis, however, DMSO elicited the strongest miotic response. After pretreatment with atropine, DMSO-induced miotic response was not affected, showing similar changes with control group. CONCLUSIONS: Taken together, it is concluded that DMSO induces miosis by inducing relaxation of iris dilator muscle.
Animals ; Atropine ; Detergents ; Dimethyl Sulfoxide* ; Injections, Intraperitoneal ; Iris* ; Miosis ; Miotics ; Pentobarbital ; Pupil ; Rats* ; Relaxation