Stress has been regrarded as one of the causes of central serous chorioretinopathy. We studied the effect of Hexamethonium (ganglionic blocking agent) on experimentaI serous chorioretinopathy following epinephrine injection in rabbits. In group 1, we injected the 0.1 % epinephrine into the rabbits through IV route for 10 days and in group 2, we addited Hexamethonium subcutaneously prior to injection of the epinephrine same term of gorup 1. We could find slight histological changes in gorup 2 as com paired with group 1, which produced serous chorioretinopathy, under the electronmicroscopic study so we would expect the preventive effect of Hexamethonium on the stress-induced serous chorioretinopathy.
Central Serous Chorioretinopathy ; Epinephrine ; Hexamethonium* ; Rabbits*

Stress has been regrarded as one of the causes of central serous chorioretinopathy. We studied the effect of Hexamethonium (ganglionic blocking agent) on experimentaI serous chorioretinopathy following epinephrine injection in rabbits. In group 1, we injected the 0.1 % epinephrine into the rabbits through IV route for 10 days and in group 2, we addited Hexamethonium subcutaneously prior to injection of the epinephrine same term of gorup 1. We could find slight histological changes in gorup 2 as com paired with group 1, which produced serous chorioretinopathy, under the electronmicroscopic study so we would expect the preventive effect of Hexamethonium on the stress-induced serous chorioretinopathy.
Central Serous Chorioretinopathy ; Epinephrine ; Hexamethonium* ; Rabbits*

The purpose of this paper is to investigate the possible correlation between the choroidal blood flow and the amplitude of the b-wave in albino rabbits. The following vasoactive drugs were administered intravenously in order to change the blood flow, and the blood flow and the ERG were measured in the dark room after 30 minutes' dark adaptation. Epinephrine (0.5 mg/kg) produced slight reduction in the b-potential only when the blood flow decreased more than 10%. Pitressin (0.1 micro/kg) induced marked degree of blood flow reduction and this changes were always associated with parallel reduction in the b-potentiaI. Papaverine (2 mg/kg) also produced marked increase in blood flow and marked increase in the bpotential parallel to it. Hexamethonium bromide (1 mg/kg) produced parallel changes in the blood flow and the b-potential only when the blood flow decreased. Reserpine (0.2 mg/kg) induced moderate increase in the blood flow and this increase was associated with the increase in the b-potential. The possible applications of these results in the clinical practice were discussed.
Choroid* ; Dark Adaptation ; Epinephrine ; Hexamethonium ; Papaverine ; Rabbits* ; Reserpine ; Vasopressins

The Effects of Some Autonomic Drugs on the Elevated Intraocular Tension of the Rabbit were Investigated. 1) Intravenous or local administration of Acetylcholine isoproterenol, a small dose of epinephrine and local large dose of epinephrine shortened the recovery time of the elevated. intraocular tension of normal level. 2) Intravenous or local administration of norepinephrine and intravenous large dose of epinephrine lengthened the recovery time. 3) A small dose of intravenous dimethylphenylpiperazinium shortened the recovery time, while large dose of the former lengthened the latter. 4) Intravenous hexamethonium, Bretylium, regitine, and small dose of atropine lengthened it From the above results, it is suggested that there are cholinergic, adrenergic alpha and beta receptor in the regulatory organs of the intraocular tension and autonomic nervous system plays an important role in regulating the intraocular tension.
Acetylcholine ; Atropine ; Autonomic Agents* ; Autonomic Nervous System ; Dimethylphenylpiperazinium Iodide ; Epinephrine ; Hexamethonium ; Isoproterenol ; Norepinephrine ; Phentolamine

PURPOSE: To identify the characteristics and physiological function of the nicotinic receptor expressed in human retinoblastoma cells. METHODS: We measured possible nicotinic signaling in WERI-Rb-1 cells using the Ca2+ imaging technique and the patch clamp method. RESULTS: 1) Nicotine-induced [Ca2+]i rise arose entirely through Ca2+ influx, which was completely abolished by hexamethonium (100 micro M). 2) Nicotine also induced remarkable depolarization from -56.6 +/- 3.7 mV to -29.6 +/- 3.6 mV (n=4) under current clamp mode, but it failed to directly activate the T-type Ca2+ channel expressed in retinoblastoma cells. CONCLUSIONS: Nicotinic activation can increase the intracellular calcium level through calcium influx in the undifferentiated retinoblastoma cells, which may play important roles in cell proliferation, differentiation, and cell death.
Calcium ; Cell Death ; Cell Proliferation ; Hexamethonium ; Humans* ; Nicotine ; Receptors, Nicotinic* ; Retinoblastoma*

Background: This study was designed to determine whether presynaptic receptor blockade could be differentiated from postsynaptic receptor blockade by examining the effect of increasing frequencies of indirect stimulation on partial twitch depression in vitro rat phrenic nerve hemidiaphragm preparations. Methods: After isolating rat phrenic nerve hemidiaphragm preparation, T200/T1 ratio (twitch height of the 200th stimuli divided by that of the 1st stimuli) at frequencies of 0.2, 0.5, 1.0, and 2.0 Hz using a drug concentration which provided approximately 20% twitch depression at 0.1 Hz was calculated. To compare T200/T1 ratios with TOF ratios, 2.0 Hz TOF response was measured immediately after 200th stimuli at either frequency of stimulation. Results: Hexamethonium caused a marked decrease in T200/T1 ratio at 0.5~2.0 Hz of stimulation, whereas alpha-bungarotoxin caused no change in T200/T1 ratios at up to 2.0 Hz of stimulation. The T200/T1 ratios produced by d-tubocurarine, vecuronium, mivacurium, and rocuronium located intermediate between alpha-bungarotoxin and hexamethonium, however significant differences among four drugs were found at 2.0 Hz. The propensity for decrease in T200/T1 ratios at 2.0 Hz might differ from this study: hexamethonium >d-tubocurarine >rocuronium >mivacurium = vecuronium >alpha-bungarotoxin. T200/T1 ratios at 2.0 Hz were not different from TOF ratios. Conclusions: When the observed effects in this study were provided with result of alpha-bungarotoxin acting predominantly at postsynaptic receptors and hexamethonium acting predominantly at presynaptic receptors, the effects of nondepolarizing muscle relaxants at each binding site could be differentiated by examining the T200/T1 ratios at 2.0 Hz.
Animals ; Binding Sites ; Bungarotoxins ; Depression* ; Hexamethonium ; Phrenic Nerve* ; Rats* ; Receptors, Presynaptic ; Tubocurarine ; Vecuronium Bromide

BACKGROUND: Interactions of neuromuscular blocking agents are antagonistic in a combination of depolarizing and nondepolarizing agents, additive in a combination of relative two compounds or synergistic in a combination of different two nondepolarizing agents. However, the interactions of neuromuscular blocking agents with a different site of action from each other have not been studied clearly. This study was designed to examine the interaction between hexamethonium and lidocaine, alpha-bungarotoxin or decamethonium with markedly different pre and postsynaptic sites of action. METHODS: Square wave, 0.1 Hz supramaximal stimuli or 2 Hz, 0.2 ms train of four (TOF) stimuli, was applied to the rat phrenic nerve-hemidiaphragm preparation, and the twitch height response was recorded mechanomyographically. The cumulative concentration effect and TOF ratio at each point of twitch depression after hexamethonium, lidocaine, alpha-bungarotoxin or decamethonium given were measured. The EC50 and EC95 of hexamethonium, lidocaine, alpha-bungarotoxin and decamethonium were calculated using an inhibitory sigmoid Emax model. In the experiment of each combination of two drugs, three points of the isobole for hexamethonium-lidocaine, hexamethonium-alpha-bungarotoxin and hexamethonium-decamethonium were established using ratios of 1 : 3, 1 : 1 and 3 : 1 of their EC50. Points on the line of theoretical additivity and 95% confidence intervals were calculated according to Tallarida et al. TOF ratios were observed at 75, 50 and 25% of the control twitch height value during each combination ratio of their EC50. RESULTS: Significant deviations of points on the isobole from the line of additivity to the left were found at all EC50 ratios of hexamethonium-lidocaine (P < 0.05 respectively), that to the right was found at all EC50 ratios of a hexamethonium-alpha-bungarotoxin and hexamethonium-decamethonium (P < 0.05 respectively). The magnitude of TOF fade depended upon the mixed ratios for their EC50. CONCLUSIONS: The interaction was found to be synergistic in the combination of hexamethonium- lidocaine, and antagonistic in the combination of hexamethonium-alpha-bungarotoxin and hexamethonium- decamethonium.
Animals ; Bungarotoxins* ; Colon, Sigmoid ; Depression ; Hexamethonium* ; Lidocaine* ; Neuromuscular Blocking Agents ; Rats

BACKGROUND: Hexamethonium (HM) and Rocuronium (R) are nAChR antagonists. However, there is some controversy as to whether R has a selective presynaptic effect. (-)Vesamicol (V) inhibits the transport of acetylcholine into the vesicles. This study compared the neuromuscular blockade of HM, R and V. METHODS: Hemidiaphragm-phrenic nerve preparations (male Sprague-Dawley rats [150-250 g]) were bathed in a Krebs solution maintained at 32oC and aerated with a mixture of 95% O2 and 5% CO2. Isometric forces were generated in response to 0.1 Hz, and 1.9-second 50 Hz with supramaximal stimulation (0.2 ms, rectangular) of the phrenic nerve. HM, R and V were added sequentially to achieve an 80-90% decrease in the ST. The ECs for ST, PTT and TF were calculated using a probit model. The antagonism indices of calcium (5 mM) and neostigmine (N) (250 nM) were assessed at the 85+/-5% level. RESULTS: The potency of ST, PTT and TF were respectively, 5.92, 3.56 and 1.99 mM for HM, 10.81, 5.27 and 4.4 1micronM for R, and 19.4, 15.2 and 13.3micronM for V. The neuromuscular blockades of R were reversed by N but not by calcium. Those of V were not reversed by either of them. Calcium and N inhibited the decrease in ST and TF by HM, respectively. CONCLUSIONS: The mechanism for how HM and R affect the neuromuscular blockade are different. V might not affect the release of acetylcholine.
Acetylcholine ; Baths ; Calcium ; Hexamethonium* ; Neostigmine ; Neuromuscular Blockade* ; Phrenic Nerve ; Rats, Sprague-Dawley

We performed a primary vitrectimy using scleral depression technique for uncomplicated rhegmetogenous retinal detachment and intended to highlight the importance of scleral depression technique. The indications for the primary vitrectomy were eyes with multiple or posteriorly located retinal breaks, unidentified retinal breaks, vitreous opacities, strong vitreous tractions on the retina tear flap, and aphakic/pseudophakic retinal detachments, Removal of vitreoretinal traction and vitreous base dissection using scleral depression technuque were performed in sixty-eight eyes of rhegmatogenous retinal detachment uncomplicated with proliferative vitreoretinopathy of grade C or worse. Scleral segmental buckle or encircling was also placed in 60 of 68 eyes. The retina was reattached after the primary operation in fifty-seven eyes(80.9%), and after reoperations in remaining eleven eyes(19.1%). Postoperative visual acuity was 0.4 or better in thirty-eight eyes (55.9%), and worse than 0.025 in eight eyes(11.8%). Vitrectomy in conjuction with scleral depression technique would be effective in increasing surgical success rate in selected cases of retinal detachment surgery.
Depression ; Hexamethonium* ; Retina ; Retinal Detachment* ; Retinal Perforations ; Retinaldehyde* ; Traction ; Visual Acuity ; Vitrectomy* ; Vitreoretinopathy, Proliferative

AIM: To study the minor diterpenes from the soft coral Sinularia depressa METHOD: The chemical constituents were isolated and purified by various chromatographic techniques, and the chemical structures, including absolute configuration, were established on the basis of detailed analysis of spectroscopic data and by literature comparison with the data of related known compounds. RESULTS: A new casbane-type diterpene, 2-epi-10-hydroxydepressin (1), was isolated and identified. CONCLUSION Compound 1 is a new casbane-type diterpene.
Animals ; Anthozoa ; chemistry ; Diterpenes ; isolation & purification ; Heterocyclic Compounds, 3-Ring ; Hexamethonium ; analysis ; Spectrum Analysis