The effect of harmaline on intestinal sodium transport and on sodium-dependentd-glucose transport in brush-border membrane vesicles from rabbit jejunum

Harmaline inhibition of sodium uptake and of sodium-dependentd-glucose transport was investigated using brush-border membrane vesicles from frozen rabbit jejunum. Under sodium-gradient conditions, initiald-glucose uptake (20 s) was inhibited by harmaline at concentrations above 0.5 mM, but at lower harmaline concentrationsd-glucose uptake was stimulated by 10–15%. When a similar potassium gradient was used, harmaline had no effect. At concentrations upt to 2 mM, harmaline did not alter the equilibrium uptake ofd-glucose ord-mannitol. After pre-equlibration with sodium (25 mM),d-glucose uptake was inhibited at harmaline concentrations ranging from 0.1 to 2 mM. Sodium (10 mM) uptake was also inhibited by harmaline. Increasing the sodium concentration reduced the inhibitory effect of harmaline on tracer sodium uptake as well as on sodium-dependentd-glucose uptake. Similar to phlorizin, harmaline (1 mM) was able to prevent glucose-induced sodium influx across the brush-border membrane.Sodium uptake into brush-border membrane vesicles seems to be inhibited at lower harmaline concentrations than sodium-dependentd-glucose uptake. At high (2 mM) inhibitor concentrations, however, sodium-dependent glucose uptake is more strongly inhibited than sodium uptake. These results suggest that harmaline inhibits both sodium and sodium-dependent transport across intestinal brush-border membranes by interacting with specific sodium-binding sites.     

Stimulus-dependent activation of c-Fos in neurons and glia in the rat cerebellum

The intent of the present study was to use chemical or electrical stimulation of cerebellar afferents to determine how different stimulation paradigms affect the pattern of activation of different populations of neurons in the cerebellar cortex. Specifically, we analyzed immediate changes in neuronal activity, identified neurons affected by different stimulation paradigms, and determined the time course over which neuronal activity is altered. In the present study, we used either systemic (harmaline) or electrical stimulation of the inferior cerebellar peduncle (10 and 40 Hz) to alter the firing rate of climbing and mossy fiber afferents to the rat cerebellum and an antibody made against the proto-oncogene, c-fos, as a marker to identify activated neurons and glia. In control animals, only a few scattered granule cells express nuclear Fos-like immunoreactivity. Although no other cells show Fos-like immunoreactivity in their nuclei, Purkinje cells express Fos-like immunoreactivity within their somatic and dendritic cytoplasm in control animals. Within 15 min of chemical or electrical stimulation, numerous granule and glial cells express Fos-like immunoreactivity in their nuclei. Cells in the molecular layer express Fos-like immunoreactivity following harmaline stimulation in a time and lobule specific manner; they do not appear to be activated in the electrical stimulation paradigm. Following harmaline injections, there is an initial loss of Fos-like immunoreactivity in the cytoplasm of Purkinje cells; 90 min later, nuclear staining is observed in a few scattered Purkinje cells. Following electrical stimulation, the cytoplasmic staining in Purkinje cells is enhanced; it is never present in the nucleus. Data derived from this study reveal cell-specific temporal and spatial patterns of c-Fos activation that is unique to each paradigm. Further, it reveals the presence of an activity dependent protein in the cytoplasm of Purkinje cell somata and dendrites.     

Effect of Liposome—Encapsulated Total Alkaloid of Harmaline on Rabbit Lens Epithelial Cells：Experimental Study on the Prevention of Posterior Capsule Opacification

Purpose: To investigate whether liposome encapsulated total alkaloid of Harmaline (TAH) as a therapeutic agent is beneficial to prevention of posterior capsular opacifi-cation (PCO).Methods: Liposome-encapsulated TAH was prepared by modified freeze-thawing method. 0. 1ml of liposome-encapsulated TAH (0. 2mg/ml) was injected into the capsular bag during extracapsular lens extraction (ECLE) of each eye in total 10 rabbit eyes. Blank liposome or balance salt solution (BSS) was used as control. Slit-lamp examination and histopathological examination was used to evaluated capsule opacifica-tion. Intraocular pressure (IOP) , density and morphology of corneal endothelia cells, the amplitude and latency of b wave of ERG were measured.Results: The inflammatory response was mild both in TAH treated and the control group. PCO formation occurred in the control group 2 weeks postoperatively, but the posterior capsule was clear in TAH treated eyes. 4 weeks and 8 weeks after operation, PCO occurred both in TAH treated     

Alteration of intracellular pH and activity of CA3-pyramidal cells in guinea pig hippocampal slices by inhibition of transmembrane acid extrusion

Transmembrane acid extruders, such as electroneutral operating Na(+)/H(+)-exchangers (NHE) and Na(+)-dependent Cl(-)/HCO(3)(-)-exchangers (NCHE) are essential for the maintenance and regulation of cell volume and intracellular pH (pH(i)). Both of them are hypothesised to be closely linked to the control of excitability. To get further information about the relation of neuronal pH(i) and activity of cortical neurones we investigated the effect of NHE- and/or NCHE-inhibition on (i) spontaneous action potentials and epileptiform burst-activity (induced by bicuculline-methiodide, caffeine or 4-aminopyridine) and (ii) on pH(i) of CA3-neurones. NHE-inhibition by amiloride (0.25-0.5 mM) or its more potent derivative dimethylamiloride (50 microM) and NCHE-inhibition by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS, 0.25-0.5 mM) induced a biphasic alteration of neuronal activity: an initial, up to 30 min lasting, increase in frequency of action potentials and bursts preceded a growing and partially reversible suppression of neuronal activity. In BCECF-loaded neurones the pH(i), however, continuously decreased during either amiloride- or DIDS-treatment and reached its steady-state (DeltapH(i) up to 0.3 pH-units) when the neuronal activity was markedly suppressed. Combined treatment with amiloride (0.5 mM) and DIDS (0.5 mM) or treatment with harmaline alone (0.25-0.5 mM), which also continuously acidified neurones via inhibition of an amiloride-insensitive NHE-subtype, induced a monophasic and partially reversible suppression of neuronal activity. As an initial excitatory period failed to occur during combined NHE/NCHE-inhibition we speculate that its occurrence during amiloride- or DIDS-treatment resulted rather from disturbances in volume- than in pH(i)-regulation. The powerful inhibitory and anticonvulsive properties of NHE- and NCHE-inhibitors, however, very likely based upon intracellular acidification - as derived from our previous findings that a moderate increase in intracellular free protons is sufficient to reduce membrane excitability of CA3-neurones.     

Monoamine Oxidase Inhibitor Poisoning Resulting from Internet Misinformation on Illicit Substances

The Internet may represent a new mechanism by which adolescents initiate the use of illicit substances. The existence of multiple partisan websites providing misinformation regarding the safety of these substances may lead to an increase in unsafe behavior among this age group. Adverse outcomes related to Internet‐based drug information are rarely identified. We report a case of an adolescent whose use of the Internet to obtain drug information led to severe poisoning from the combination of a monoamine oxidase inhibitor, harmaline, and a hallucinogenic tryptamine, 5‐methoxydimethyltryptamine (5‐MeO‐DMT).     

Harmaline effects on the sensory-motor reactivity: Modifications of the acoustic startle pattern

The effects of harmaline, an indoleamine and a MAOI, were tested on the acoustic stratle pattern. EMG measures of the startle reflex, the pinna reflex as well as the characteristic of the vertex evoked responses to brief intense tone burst (60 msec, 110 dB,8000 Hz) were simultaneously studied in 4 alert guinea-pigs. The basic experimental design was a 4 latin square, with the treatments being given at 2 day intervals. The four harmaline-HCI treatments were isotonic saline, 0.25 5.0 and 10.0 mg/kg. Compared with saline baselines, all the doses resulted, throughout the 60 min session, in overall high significant depressions of the startle reflex, the pinna reflex and the initial wave of the acoustic evoked potential at the vertex. In contrast, harmaline had little or no influence on amplitude and latency of the late wave of the vertex response. The effects of harmaline on the general behavior of the guinea-pig are also reported. These results may support an involvement of serotonergic systems in the modulation of the sensory-motor reactivity at the brainstem level. Nevertheless, the probab;y more complex cortical processes involved in startle responsivity do not appear univocally affected by the indoleamine drugs such as harmaline.     

Cytotoxicity of the β-carboline alkaloids harmine and harmaline in human cell assays in vitro

beta-Carboline alkaloids are natural products widely distributed in plants and also found in alcoholic beverages, well-cooked foods and tobacco smoke. Various authors have reported genotoxic activities of several carboline in prokaryotic and eukaryotic cells that have been attributed to their abilities to intercalate into DNA. But studies on the genotoxic and on the cytotoxic potencies in human cells in vitro are not found in the literature. In the present study the toxicities of one full aromatic beta-carboline alkaloid (harmine) and one dihydro-beta-carboline alkaloid (harmaline) were evaluated by means of two in vitro human cell assays: the cytochalasin-B blocked micronucleus (CBMN) assay and the viability/colony formation assay with four different human cultured non-transformed (CCD18Lu) and transformed (HeLa, C33A and SW480) cells. Neither alkaloid was able to induce micronuclei levels above that of control levels in a wide range of doses tested; although, harmine at the highest concentrations assayed induced apoptotic as well as necrotic cells. Harmine produced a good viability of all cell lines assayed (control and tumor) while harmaline significantly reduced the viability of transformed and non-transformed cell lines in a dose-dependent manner. Harmine displayed a dose-dependent inhibitory effect on cell proliferation against all human carcinoma cells, but the SW480 transformed cell line showed a higher sensitivity. These results suggested that harmine was identified as a useful inhibitor of tumor development.     

Ethanol increases single unit activity in the inferior olivary nucleus

Single unit recording of rat inferior olivary nucleus neurons reveals significantly elevated discharge after acute intraperitoneal injection of 2 g/kg ethanol. This effect is consistent across 3 different methods of anesthesia and immobilization: local Xylocaine plus intraperitoneal D-tubocurare, intraperitoneal chloral hydrate and halothane vapor. In contrast, under urethane anesthesia acute ethanol produces significant depression of olivary discharge. Since this effect is opposite to that found under the other anesthetic conditions (including topical Xylocaine only), urethane anesthesia may compromise generalizations of electrophysiologic studies of ethanol. Neurons of the inferior olivary nucleus excite cerebellar Purkinje cells through a powerful afferent circuit; our data therefore suggest that ethanol-induced increases in cerebellar Purkinje cell complex (climbing fiber burst) spikes, obtained in our previous studies, are secondary to olivary activation.     

HPLC法同时测定哈医祛风膏中去氢骆驼蓬碱和骆驼蓬碱的含量及疗效观察

目的:建立高效液相色谱法(HPLC)测定哈医祛风膏中去氢骆驼蓬碱和骆驼蓬碱的含量及临床疗效观察。方法:采用高效液相法测定含量,色谱柱为Agilent TC-C18(4.6 mm×250 mm,5 μm),以甲醇:0.01 moL/L硫酸铵溶液(37:63,用三乙胺调pH至4.0)为流动相,流速为1 mL/min,柱温:25 ℃,检测波长在320 nm。用完全随机法分实验组和对照组进行比较哈医祛风膏疗效。结果:去氢骆驼蓬碱的线性范围为12~83 μg(r=0.999 8,n=6)平均回收率为100.14%,RSD值为1.33%、骆驼蓬碱的线性范围为12~83 μg(r=0.999 8,n=6)平均回收率为98.89%,RSD值为1.77%。疗效比较治疗组的总有效率为97.3%、对照组的总有效率为90.1%,2组有显著性差异,P<0.01。表明治疗组总体疗效明显优于对照组。结论:高效液相色谱法方法简便,准确,可靠,可以用于哈医祛风膏中去氢骆驼蓬碱和骆驼蓬碱的含量测定。并哈医祛风膏治疗颈肩腰腿痛的效果较好、疗效确切、安全性良好,可降低患者复发率,可考虑在临床上推广。     

Reduced binding of 3 H-reserpine to the hearts of 6-hydroxydopamine-pretreated rats

6-Hydroxydopamine (6-OH-DA) pretreatment of rats resulted in a consistent reduction of the small amounts of reserpine residual in the heart, 24 hr after its injection. This finding presumably depends on the destruction of sympathetic nerve terminals currently ascribed to 6-OH-DA and it indicates that reserpine in the heart is at least in part bound to adrenergic structures. The injection of harmaline and of ³H-inuline did not result in lower harmaline and tritium concentration in the hearts of 6-OH-DA pretreated rats.