This study was aimed at investigation of the stimulatory innervations on the rat urinary bladder. Detrusor muscle strips of 15 mm long were suspended in isolated muscle chambers containing 1 ml of PSS maintained at 37℃ and aerated with 95% O²/5% Co². Isometric myography was performed, and the results were as followings: Muscle strips showed “on-contraction” by electric field stimulation (EFS) frequency-dependently. The EFS-induced contraction was not affected by hexamethonium, a ganglion blocker, but abolished by tetrodotoxin, a nerve conduction blocker. Physostigmine, a cholinesterase inhibitor enhanced the EFS-induced contraction which was inhibited by hemicholinium, an inhibitor of choline uptake at the cholinergic nerve ending. Such an EFS-induced contraction was antagonized by atropine only partially, and the atropine-resistant portion was completely abolished by the desensitization of purinergic receptors by prolonged incubating of the strips in the presence of high concentration of ATP. Bethanechol, a cholinergic agonist, elicited concentration-dependent contraction. Adenosine triphosphate (ATP), a purinergic agonist, induced a weak but concentration-dependent contraction of short duration. Bethanechol-induced contraction was not affected by ATP-desensitization, and ATP-induced contraction was not affected by tetrodotoxin. These results suggest that there are at least two main stimulatory components of innervations in the detrusor muscle, cholinergic muscarinic and purinergic; and those receptors are independent each other.
Adenosine Triphosphate ; Animals ; Atropine ; Bethanechol ; Choline ; Cholinergic Agonists ; Cholinesterases ; Ganglion Cysts ; Hemicholinium 3 ; Hexamethonium ; Myography ; Nerve Endings ; Neural Conduction ; Physostigmine ; Rats* ; Receptors, Purinergic ; Tetrodotoxin ; Urinary Bladder*

This study was designed to investigate the effect of GABA and related substances on the spontaneous contraction of rat small intestine. The rats (Sprague-Dawley), weighing 200-250g, were sacrificed by cervical dislocation, and the small intestine was isolated. Longitudinal muscle strips from duodenum, jejunum and ileum were suspended in Biancani's isolated muscle chambers and myographied isometrically. GABA and muscimol, a GABA A receptor agonist relaxed the duodenum and jejunum significantly, but baclofen-induced relaxation in those muscle strips negligible. The effectiveness of GABA and muscimol in various regions were the greatest on duodenum, and greater on jejunum than on ileum The effect of GABA and muscimol was antagonized by bicuculline, a competitive GABA A receptor antagonist and picrotoxin, a noncompetitive GABA A receptor antagonist. Duodenal relaxation induced by GABA and muscimol was unaffected by hexamethonium, but was prevented by tetrodotoxin. These results suggest that GABA inhibit the contractility of smooth muscle with distinct regional difference of efficacy, and the site of inhibitory action is the GABA A receptor existing at the presynaptic membrane of postganglionic excitatory nerves.
Animals ; Bicuculline ; Dislocations ; Duodenum ; GABA-A Receptor Agonists ; GABA-A Receptor Antagonists ; gamma-Aminobutyric Acid* ; Hexamethonium ; Ileum ; Intestine, Small* ; Jejunum ; Membranes ; Muscimol ; Muscle, Smooth ; Picrotoxin ; Rats* ; Receptors, GABA-A ; Relaxation ; Tetrodotoxin

This study was performed to investigate the effect of octreotide on the contractility of rat vas deferens. The -smooth muscle strips isolated from the prostatic portion were myographied in isolated organ bath. Electric -field stimulation (monophasic square wave, duration : 1. mSec, voltage : 50 V, frequency : 5 Hz or 30 Hz, train : 10 Sec) produced reproducible contraction. The contraction was composed of two component, first phasic component (FPC) and second tonicc component (STC).. These contractions were abolished by -tetrodotoxin (1 microM). Octreotide inhibited the field stimulation induced contractions both FPC and STC concentration- dependently. The FPC was decreased by a desentization of purinergic receptor by pretreatment of mATP, and the STC was decreased by pr,,creatment of reserpine (3 mg/kg, EP) 24 hours before experiments. Octreotide reduced the field stimulation induced contraction in the presence of mATP and of reserpinized muscle strips. The inhibitory effect of octreotide was more potent at 5 Hz than at 30 Hz. Octreotide did not affect basal ton and exogenous norepinephrine- or ATP-induced contraction. These results suggest that octreotide inhibit the contractility of the isolated rat vas deferens by inhibition of the release of neurotransmitters, both ATP and norepinephrine from adrenergic nerve terminal.
Adenosine Triphosphate ; Animals ; Baths ; Neurotransmitter Agents ; Norepinephrine ; Octreotide* ; Rats* ; Reserpine ; Vas Deferens*

Lithium salts are being used increasingly to treat patient with affective disorders, especially acute mania, or bipolar manic-depressive illness. For therapeutic effect the lithium content must be maintained at or above a particular level. Lithium poisoning due to overdosage may be seen occasionally, and its course is determined primarily by the rate of renal lithium elimination. A search is therefore indicated for procedures that could raise the lithium clearance. In a number of reports renal lithium excretion has been studied in relation to the excretion of water, sodium, potassium and hydrogen, but effects of sodium or water on the lithium excretion has not yet been clarified. Hence the present study was undertaken to investigate the effects of corticosteroid on the excretion of lithium ion. The female rat (Sprague-Dowley), weighing from 200 to 300g, was injected with 50mg/kg of lithium chloride intraperitoneally, and then injected with graded dosage of fludrocortisones and dexamethasone in each group. During the injected rats were incubated in metabolic cage, 24 hour urine of rats were collected. At 24 hours after injection, the rats were sacrificed with guillotine, the blood were collected. And then the concentrations of Na⁺, K⁺, Li⁺ of collected urine and serum were checked by Flame photometer. The results are summarized as follows 1. Fludrocortisone decreased the serum concentration of lithium and increased the urinary excretion of lithium. 2. In the group treated with low dose of dexamethasone (0.1 mg/kg), the serum concentration of lithium was decreased and high dose of dexamethasone (1 mg/kg) increased the urinary excretion of lithium. 3. Fludrocortisone increased the urinary [Na⁺]/[K⁺] in serum and decreased [Na⁺]/[K⁺] inurine, but opposite effects were occurred in dexamethasone. By above results, it may be concluded that corticosteroid increased the urinary excretion of lithium and decreased the serum concentration of lithium, but it seems to be there in no relationship between these effects of corticosteroid and of the renal Na⁺ or K⁺ transport.
Adrenal Cortex Hormones* ; Animals ; Bipolar Disorder ; Dexamethasone ; Female ; Fludrocortisone ; Humans ; Hydrogen ; Lithium Chloride ; Lithium* ; Mood Disorders ; Poisoning ; Potassium ; Rats ; Renal Elimination* ; Salts ; Sodium ; Water

GABA is an inhibitory neurotransmitter in central nervous system and produce sedative, antianxiety and muscle relaxing effects via GABA(A) receptor or GABA(B) receptor. Recently it is known that GABA is widely distributed throughout peripheral organs and may play a 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 norepinephrine-, 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 prostatic portion and were mounted in the isolated muscle bath. PSS in the bath was aerated with 95/5%-O₂/CO₂ at 33℃. Muscle tensions were measured by isometric tension transducer and were recorded by biological recording system. 1. GABA, muscimol, a GABA(A) agonist, and baclofen, a GABA(B) agonist inhibited the electric field stimulation (EFS, 0.2Hz, 1mSec, 80V, 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) intagonist. 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 contractions. 6. EFS-induced contraction was inclucling 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.
Acetylcholine ; Adenosine Triphosphate ; Animals ; Baclofen ; Baths ; Bicuculline ; Central Nervous System ; Dislocations ; gamma-Aminobutyric Acid ; Muscimol ; Muscle, Smooth ; Neurons ; Neurotransmitter Agents ; Norepinephrine ; Rats* ; Rats, Sprague-Dawley ; Receptors, GABA-A ; Reserpine ; Transducers ; Vas Deferens*

To investigate the effect of diazepam on the contractility of the intestinal smooth muscle, longitudinal muscle strip isolated from rat ileum was prepared for myography in isolated organ bath. 1) Basal tone of ileal muscle was reduced by diazepam concentration-dependently. 2) Higher concentrations (30 and 100 microM) of diazepam inhibited (p<0.05, p<0.001) The carbachol-induced contraction in a concentration-dependent manner; but lower concentration of diazepam (10 microM) enhanced (p<0.05). 3) Histamine-induced contraction was inhibited by pretreatment with diazepam in a concentration-dependent manner. 4) Ca⁺⁺-induced tension recovery in calcium-free solution was inhibited in the presence of diazepam concentration-dependently. These results suggest diazepam reduces the contractility of the longitudinal muscle isolated from rat ileum via interference with influx of calcium into the muscle cells.
Animals ; Baths ; Calcium ; Carbachol* ; Diazepam* ; Ileum* ; Muscle Cells ; Muscle, Smooth ; Myography ; Rats*

This study was designed to investigate the effect of diazepam on the spontaneous contraction and oxytocin induced contraction of the isolated rat uterus. Female rat (Sprague-Dawley) pretreated with oophorectomy and 4 days administration of estrogen. Weighing about 200 g, was sacrificed by cervical dislocation, and the uteruses were isolated. A longitudinal muscle strip was placed in temperature controlled (37℃) muscle chamber containing Locke's solution and myographied isometrically. Diazepam inhibited the spontaneous contraction and oxytocin induced contraction of the isolated rat uterus in a concentration-dependent manner. GABA, muscimol, a GABA A receptor agonist, bicuculline, a competitive GABA A receptor antagonist, picrotoxin, a non competitive GABA A receptor antagonist, baclofen, a GABA B receptor agonist, and delta-aminovaleric acid, a GABA B receptor antagonist, did not affect on the spontaneous and oxytocin induced contraction of the isolated rat uterus. The inhibitory actions of diazepam on the spontaneous and oxytocin induced contraction were not affected by all the GABA receptor agonists and antagonists, but exceptionally potentiated by bicuculline. This potentiation-effect by bicuculline was not antagonized by muscumol. In normal calcium PSS, addition of calcium restored the spontaneous contraction preinhibited by diazepam and recovered the contractile of oxtrocin preinhibited by diazepam. A23187, a calcium inophore, enhanced the restoration of both the spontaneous and oxytocin induced contraction by addition of calcium. In calcium-free PSS, diazepam suppressed the restoration of spontaneous motility by addition of calcium but allowed the recovery of spontaneous motility to a considerable extent. Diazepam could not inhibit some development of contractility by oxytocin in calcium-free PSS, but inhibited the increase in contractility by subsequent addition of calcium. These results suggest that the inhibitory action of diazepam on the rat uterine motility does not depend on or related to GABA receptors and that diazepam inhibits the extracellular calcium influx to suppress the spontaneous and oxytocin induced contractilities.
Animals ; Baclofen ; Bicuculline ; Calcimycin ; Calcium ; Diazepam* ; Dislocations ; Estrogens ; Female ; GABA Agonists ; GABA-A Receptor Agonists ; GABA-A Receptor Antagonists ; GABA-B Receptor Agonists ; GABA-B Receptor Antagonists ; gamma-Aminobutyric Acid ; Humans ; Muscimol ; Ovariectomy ; Oxytocin* ; Picrotoxin ; Rats* ; Receptors, GABA ; Uterus*

BACKGROUND: Spirometry should be compared with the normal predictive values obtained from the same population using the same procedures, because different ethnicity and different procedures are known to influence the spirometry results. This study was performed to obtain the normal predictive values of the Forced Vital Capacity(FVC), Forced Expiratory Volume in 1 Second(FEV1), Forced Expiratory Volume in 6 Seconds(FEV6), and FEV1/FVC for a representative Korean population. METHODS: Based on the 2000 Population Census of the National Statistical Office of Korea, stratified random sampling was carried out to obtain representative samples of the Korean population. This study was performed as a part of the National Health and Nutrition Survey of Korea in 2001. The lung function was measured using the standardized methods and protocols recommended by the American Thoracic Society. Among those 4,816 subjects who had performed spirometry performed, there was a total of 1,212 nonsmokers (206 males and 1,006 females) with no significant history of respiratory diseases and symptoms, with clear chest X?rays, and with no significant exposure to respiratory hazards subjects. Their residence and age distribution was representative of the whole nation. Mixed effect models were examined based on the Akaike's information criteria in statistical analysis, and those variables common to both genders were analyzed by regression analysis to obtain the final equations. RESULTS: The variables affecting the normal predicted values of the FVC and FEV6 for males and females were age2, height, and weight. The variables affecting the normal predicted values of the FEV1 for males and females were age2, and height. The variables affecting the normal predicted values of the FEV1/FVC for male and female were age and height. CONCLUSION: The predicted values of the FVC and FEV1 was higher in this study than in other Korean or foreign studies, even though the difference was < 10%. When compared with those predicted values for Caucasian populations, the study results were actually comparable or higher, which might be due to the stricter criteria of the normal population and the systemic quality controls applied to the whole study procedures together with the rapid physical growth of the younger generations in Korea.
Age Distribution ; Censuses ; Family Characteristics ; Female ; Forced Expiratory Volume ; Humans ; Korea ; Lung ; Male ; Nutrition Surveys ; Quality Control ; Spirometry* ; Thorax

OBJECTIVE: This study was designed to assess the influences of skin temperature and age on latency and amplitude of the sympathetic skin response (SSR). METHOD: We examined the sympathetic skin responses in 77 normal subjects aged 25 to 73 years. With stimulation of both median nerve and both tibial nerve at the wrist and ankle, the SSRs were recorded from both palms and soles simulaneously. To determine the effects of skin temperature change on SSR, we examined the SSRs in 12 healthy subjects before and after heating. The heat was applied on right forearm by infra-red lamp. RESULTS: The mean latency and the mean amplitude of SSR with stimulation of the right median nerve at the wrist were 1.47 sec and 6.08 mV at the right palm, 1.50 sec and 6.07 mV at the left palm, 1.95 sec and 3.38 mV at right sole, and 1.95 sec and 3.09 mV at left sole. There was no side-to-side difference in the latency and the amplitude. Regardless of the site of stimulation, latency was longer at the sole than at the palm, and amplitude was greater at the palm than at the sole (p<0.05). The latency of the SSR was positively correlated with the age of subjects (p<0.05), and the amplitude was negatively correlated with the age of subjects (p<0.05). At higher skin temperature, the latency of SSR was shortened and the amplitude was reduced significantly (p<0.05). CONCLUSION: The amplitude of the SSR decreases with aging and the latency increases with aging. As the skin temperature rises, the latency and amplitude show tendency to decrease. We suggest that the skin temperature and age are important factors to be considered carefully in assessing the SSR parameters.
Aging* ; Ankle ; Forearm ; Heating ; Hot Temperature ; Median Nerve ; Skin Temperature* ; Skin* ; Tibial Nerve ; Wrist

BACKGROUND: We performed this study to evaluate the potency and time course of rocuronium-induced neuromuscular block following moderate or severe acute normovolemic hemodilution (ANH) in rabbits. METHODS: Forty five rabbits were randomly assigned to the control (C) group, the moderate ANH (M) group, or the severe ANH (S) group. After stabilization of sevoflurane anesthesia, ANH was achieved by drainage of arterial blood and an intravenous infusion of 6% hydroxyethyl starch, during which hematocrit (Hct) decreased to 26.2 ± 2.5% in the M group and 17.6 ± 2.2% in the S group. We determined dose-response relationships of rocuronium in the three groups and created a time course of the action of 0.6 mg/kg rocuronium. RESULTS: The 50% effective dose (ED50) for rocuronium was 45% and 50% lower in the M and S groups, respectively, than in the C group (50.9 ± 6.3 µg/kg) (P < 0.001). The onset time after 0.6 mg/kg rocuronium was faster in the ANH groups compared with the C group (P < 0.001). The duration of neuromuscular block was prolonged by 38% and 43% in the M and S groups, respectively, compared with the C group (49.1 ± 6.9 min) (P < 0.001). CONCLUSIONS: ANH resulted in high potency, rapid onset, and prolonged duration of rocuronium. However, the severity of ANH did not alter the potency and duration of action of rocuronium.
Anesthesia ; Drainage ; Hematocrit ; Hemodilution* ; Infusions, Intravenous ; Neuromuscular Blockade ; Rabbits* ; Starch