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

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

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*

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*

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

BACKGROUND: The actions of mivacurium (MVC), a new benzylisoquinolinium nondepolarizing neuromuscular blockade, may be potentiated if preceded by succinylcholine (SCh). Additionally, the interaction between inhalational anesthetics and MVC has not yet been established in the cat. The effect of enflurane or isoflurane on the neuromuscular blocking action of MVC by preadministrated succinylcholine was evaluated. METHOD: Twelve cats, either sex, were assigned into two groups, based on the preadministration of succinylcholine (SCh) what about the sciatic nerve-anterior tibialis preparation, cumulative dose-response study and the estimation of recovery profiles from the twitch depression of about 95 % under pentobarbital, isoflurane or enflurane anesthesia was done. The ED50, ED95 and the recovery profiles were compared. RESULTS: The ED50 and ED95 under isoflurane (24.5 & 37.3) and enflurane (20.6 & 32.1) were significantly lower than those under pentobarbital anesthesia(28.4 & 42.9 ug/kg, respectively) without preadministrated SCh. The effective doses of MVC with preadministrated SCh had the same manner. The recovery profiles under enflurane anesthesia were significantly slower than those under pentobarbital anesthesia. The higher the recovered twitch height under enflurane anesthesia, the slower the recovery speed. CONCLUSION: The potency of MVC and recovery profiles under inhalation anesthetics are greater than those under pentobarbital. However, preadministrated SCh causes no significant difference in its potency or recovery.
Anesthesia ; Anesthetics ; Anesthetics, Inhalation ; Animals ; Cats* ; Depression ; Enflurane* ; Isoflurane* ; Neuromuscular Blockade* ; Pentobarbital ; Pharmacology ; Succinylcholine*

The effect of elevated mixed venous oxygen tension(PvO2) on the diffuse alveolar hypoxia was studied in dogs using venovenous(VV) extracorporeal lung assist(ECLA). Six mongrel dogs were mechanically ventilated with the continous infusion of pentobarbital. A double lumen tube was inserted via the right external jugular vein and was eonnected with the ECLA cireuit to establish a VV bypass. A Kurare oxygenator 0.3m2 was chosen to obviate the use of homologous blood for priming. The total volume of the ECLA circuit was 150mL Without ventilating the oxygenator during VV ECLA, we decreased F1O2 from 0.21 to 0.1 via 0.15 to evaluate the hypoxic repsonse of lung. Stepwise reductions in F1O2 0.21 to 0.l caused the arterial oxygen tension(PvO2) and (PvO2 to decrease while the mean pulmonary arterial pressure(MPAP) and pulmonary vascular resistance(PVR) progressively increased. We hypothesized that the reduction of F1O2 without aceompanying decrease of PvOmight not induce hypoxic pulmonary vasoconstriciton(HPV) which was proved at low F1O2 with low PvO VV ECLA was tried on another 7 dogs while monitoring arterial oxygen saturation(SaO2) and mixed venous oxygen saturation(SvO2) by two oximetrix catheters. The elevation of SvO2 during VV ECLA was followed by the elevation of SaO2 We compared MPAP and PVR at high F1O2 with those at low F1O2with VV ECLA while making SaO2 equal. PvO2 were 39+/-11mmHg at F1O2 0.21 and 62+/-11mmHg at F1O2 0.15 with VV ECLA. PvO2 were 30+/-8mmHg at F1O2 0.15 and 53+/-10mmHg at F1O2 0.1 with VV ECLA. MPAP and PVR were 18+/-5mmHg and 176+/-56 dyne sec/cm5 at F1O2 0.21 and 19+/-4mmHg and 198+/-94 dyne sec/cm5 at F1O2 0.15 with VV ECLA . MPAP and PVR were 25 5 mmHg and 430+/-250 dyne. sec/ cm5 at F1O2 0.15 and 25+/-5mmHg and 400+/-197 dyne sec/cm5 at F1O2 0.1 with VV ECLA. Decrease of F1O2 from 0.21 to 0.15 and from 0.15 to 0.1 did not cause significant ehanges in MPAP and PVR during VV ECLA. Our findings indicate that small increase of PvO2 by VV ECLA may prevent or diminish hypoxic resyonse of the whole lung.
Animals ; Anoxia ; Catheters ; Dogs* ; Jugular Veins ; Lung* ; Oxygen ; Oxygenators ; Pentobarbital ; Pulmonary Circulation*

In determination of brain death, brain CT angiography (CTA) can be used as a new ancillary test to assist EEG which is the current gold standard. We report a patient with barbiturate coma therapy whose CTA showed weak filling of the internal carotid artery and its branches when his EEG demonstrated regional beta activities in the corresponding area, which finally disappeared. Combined use of CTA and serial EEGs would be helpful as brain death testing in a patient with barbiturate coma therapy.
Angiography* ; Brain Death* ; Brain* ; Carotid Artery, Internal ; Coma* ; Electroencephalography ; Humans ; Pentobarbital ; Subarachnoid Hemorrhage*

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

It was investigated if regulation of the trabecular extracellular matrix tumover rate and remodeling plays an important role in decreasing outflow resistance by determining the effect of intracamerally given interleukin-1alpha a known stimulator of the expression of trabecular matrix metallopro-teinases, on outflow facility of albino rat eyes. Forty normal albino rats (Sprague dawley) weighing 250 to 300gm were studied. Rats were anesthetized by intraperitoneal pentobarbital sodium(30mg/kg) injection. The rats were grouped into 4 groups and given 5, 10, 25, 50 units of interleukin-1alpha injected intracamerally in one eye of each rat. Bovine serum albumin in phosphate buffered saline, which was used to dissolve the interleukin-1alpha, was injected in the other eye as a control. Outflow facility was measured by two level constant pressure perfusion at 1, 3, and 7 days after injection. The eyes treated with 50 units of interleukin-1alpha showed a statistically significant increase of outflow facility by 37% compared to the contralateral control eyes at 3 days after injection, but retumed to normal level in 7 days. The eyes treated with 5, 10, 25, 50 units of interleukin-1alpha increased the outflow facility, supporting the hypothesis that regulation of trabecular meshwork extracellular matrix plays a role in trabecular outflow resistance.
Animals ; Extracellular Matrix ; Interleukin-1alpha* ; Interleukins ; Pentobarbital ; Perfusion ; Rats* ; Serum Albumin, Bovine ; Trabecular Meshwork