Cl– secretion induced by 5-hydroxytryptamine and calcitonin gene-related peptide in rat tracheal epithelia

 The effects of 5-hydroxytryptamine (5-HT) and calcitonin gene-related peptide (CGRP), which are colocalized in nerve terminals in the airway, on Cl^– secretion in rat tracheal epithelia were tested. Short-circuit current (I _sc) was measured after rat tracheal epithelial monolayers were cultured on porous filters. In rat tracheal monolayers 5-HT and CGRP increased I _sc upon addition to the serosal compartment, in a dose-dependent manner with EC₅₀ values at 5 μmol/l and 5 nmol/l, respectively. The responses were dependent on the presence of Cl^– in the bathing solution and were inhibited by 100 μmol/l bumetanide. When 5-HT or CGRP was added after the administration of forskolin, the responses were not observed. 5-HT and CGRP increased the intracellular cAMP concentration. Low-Ca²⁺ buffer (0.1 mmol/l) and pretreatment with BAPTA/AM (10 μmol/l), thapsigargin (1 μmol/l) or indomethacin (10 μmol/l) did not affect the responses to 5-HT and CGRP. The 5-HT-induced response was not inhibited by 5-HT₂ and/or 5-HT₄ antagonists. These results indicate that in the rat tracheal epithelia 5-HT and CGRP increase Cl^– secretion by an increase in intracellular cAMP concentration via direct activation of basolateral receptors, and that the response to 5-HT is not mediated via 5-HT₄ receptors. Received: 8 January 1997 / Received after revision: 11 June 1997 / Accepted: 23 July 1997     

Whole-cell conductive properties of rat pancreatic acini

Acetylcholine-controlled exocrine secretion by pancreatic acini has been explained by two hypotheses. One suggests that NaCl secretion occurs by secondary active secretion as has been originally described for the rectal gland of Squalus acanthias. The other is based on a “push-pull” model whereby Cl⁻ is extruded luminally and sequentially taken up basolaterally. In the former model Cl⁻ uptake is coupled to Na⁺ and basolateral K⁺ conductances play a crucial role, in the latter model, Na⁺ uptake supposedly occurs via basolateral non-selective cation channels. The present whole-cell patch-clamp studies were designed to further explore the conductive properties of rat pancreatic acini. Pilot studies in approximately 300 cells revealed that viable cells usually had a membrane voltage (V _m) more hyperpolarized than −30 mV. In all further studies V _m had to meet this criterion. Under control conditions V _m was −49 ± 1 mV (n = 149). The fractional K⁺ conductance (f _K) was 0.13 ± 0.1 (n = 49). Carbachol (CCH, 0.5 μmol/l) depolarized to −19 ± 1.1 mV (n = 63) and increased the membrane conductance (G _m) by a factor of 2–3. In the seeming absence of Na⁺ [replacement by N-methyl-D-glucamine (NMDG⁺)] V _m hyperpolarized slowly to −59 ± 2 mV (n = 90) and CCH still induced depolarizations to −24 ± 2 mV (n = 34). The hyperpolarization induced by NMDG⁺ was accompanied by a fall in cytosolic pH by 0.4 units, and a very slow and slight increase in cytosolic Ca²⁺. f _K increased to 0.34. The effect of NMDG⁺ on V _m was mimicked by the acidifying agents propionate and acetate (10 mmol/l) added to the bath. The present study suggests that f _K makes a substantial contribution to G _m under control conditions. The NMDG⁺ experiments indicate that the non- selective cation conductance contributes little to V _m in the presence of CCH. Hence the present data in rat pancreatic acinar cells do not support the push-pull model. Received: 8 November 1995/Received after revision: 18 December 1995/Accepted: 3 January 1996     

A large,multiple-conductance chloride channel in normal human T lymphocytes

Chloride (Cl) channels have been proposed to play roles in lymphocyte functions including volume regulation and cellular cytotoxicity; however, direct studies of such channels in normal human lymphocytes are lacking. In the present study we describe a large conductance Cl channel observed in about 50% of excised, inside-out patches from normal human peripheral T lymphocytes. The channel has multiple conductance states with linear single-channel current-versus-voltage relationships in symmetrical Cl solutions. The most prevalent state is the largest, which has a conductance of about 365 pS. The channel closes in a voltage-dependent manner at both negative and positive potentials, but does not show voltage-dependent inactivation. The probability of opening is maximal between –15 mV and +15 mV and the voltage dependence is well described by two Boltzmann equations with half-maximal probabilities at –22.8 mV and +18.0 mV. The slopes of the voltage dependence suggest two gates in series with 5.7 and 9.6 equivalent charges. The channel was about 30 times more selective for Cl^– than for Na⁺ or K⁺ under balanced osmolarity but less selective (approx. 111) under a large osmotic gradient. The single-channel conductance increased with Cl concentration with an apparent saturation at about 581 pS and a Michaelis-Menten constant of about 120 mM. The selectivity sequence among anions, determined from changes in reversal potential was: I^– > NO ₃ ^– > Br^–, Cl^– > F^–, isethionate, HCO ₃ ^– > SO ₄ ^2– > gluconate, propionate > aspartate Na⁺, K⁺ and was apparently the same for subconductance states. The sequence determined from measurable values of single-channel conductance was: I^– > NO ₃ ^– > Br^– > Cl^– > F^– > HCO ₃ ^– , isethionate. The channel was rapidly and reversibly blocked by 1 mM Zn²⁺ or 1 mM Ni²⁺ added to the cytoplasmic face. Possible roles of this maxi-Cl channel in lymphocyte function are discussed.     

Increased humoral and cellular immunity in mice inoculated with allogeneic tumor cells attached to microcarrier beads

A murine carcinoma cell line was grown in a microcarrier culture and was used for immunization of allogeneic mice. It was found that inoculation of cells attached to microcarrier beads resulted in heightened serum titers of cytotoxic antibodies and in a stronger cell-mediated cytotoxic reactivity in the spleen compared to cells detached from the substrate. It is proposed that immunization of animals with anchorage-dependent cells should be carried out while the cells are still adherent to the culture microcarriers.     

咪唑类离子液体对三七中痕量成分人参皂苷Rh1的体外经皮促渗作用研究

目的 考察咪唑类离子液体([BMIM][Cl])对人参皂苷Rh1(Rh1)的体外经皮促渗作用及促渗机制。方法 以小鼠皮和猪皮为皮肤模型,以油酸、薄荷脑、肉豆蔻酸异丙酯和离子液体[BMIM][Cl]为促渗剂,采用摇瓶法测定Rh1在各促渗剂-水溶液中的溶解度;采用Franz扩散池进行体外经皮渗透实验;采用傅里叶转换红外线光谱(FTIR)法测定研究离子液体的经皮促渗机制。结果 与其他促渗剂相比,5%的[BMIM][Cl]能够显著增加Rh1在水中的饱和溶解度;同时对Rh1的体外经皮渗透有显著的促进作用。FTIR的研究结果表明,[BMIM][Cl]能够改变小鼠皮肤角质层结构。结论 [BMIM][Cl]作为一种新型的经皮吸收促渗剂,在外用制剂领域有潜在的使用价值。     

Plants used for treatment of dysentery and diarrhoea by the Bhoxa community of district Dehradun,Uttarakhand, India

Ethnopharmacological relevance

Dysentery and diarrhoea are major causes of morbidity and mortality in rural communities of developing world. The Bhoxa community is an important primitive indigenous community of Uttarakhand, India. In this paper we have tried to scientifically enumerate ethnomedicinal plants and herbal preparations used by Bhoxa community to treat dysentery and diarrhoea, and discuss their antidiarrhoeal properties in the light of previous ethnomedicinal, pharmacological, microbiological and phytochemical studies. To record plants and herbal preparations used by Bhoxa community of district Dehradun, Uttarakhand, India in treatment of dysentery and diarrhoea, and to discuss antidiarrhoeal and antimicrobial properties of the recorded plants.

Materials and methods

Ethnomedicinal survey was conducted in different villages of Bhoxa community located in district Dehradun, Uttarakhand, India. Thirty Bhoxa traditional healers were interviewed to collect information on plants used by them for treating dysentery and diarrhoea. For each of the recorded plant species the use value (UV) and fidelity level (FL) was calculated. Detailed literature survey was conducted to summarize ethnomedicinal, pharmacological, microbiological and phytochemical information on the medicinal plants listed in the present study.

Results

Fifty medicinal plants (45 genera and 30 families) were used by Bhoxa community to treat dysentery and diarrhoea, among which 27 species were used for dysentery, 41 for diarrhoea and 18 for both dysentery and diarrhoea. Three plants viz., Dioscorea bulbifera L., Euphorbia thymifolia L. and Prunus persica (L.) Stokes, recorded in the present survey have been reported for the first time in treatment of dysentery and diarrhoea by any indigenous communities in India. FL and UV values revealed that most preferred species for the treatment of dysentery and diarrhoea by Bhoxa community are Euphorbia hirta L. followed by Holarrhena pubescens Wall., Helicteres isora L. and Cassia fistula L. Earlier pharmacological studies confirmed that 27 of the recorded plants have some proven antidiarrhoeal properties and remaining 23 plants have to be pharmacologically evaluated for their antidiarrhoeal properties. Except 6 plants all the other recorded plants have shown antimicrobial properties in previous microbiological studies. Previous studies have corroborated the ethnomedicinal claims made by the traditional healers of the Bhoxa community.

Conclusions

Present study has provided new information on many medicinal plants and their uses. All the three newly reported plants for treatment of dysentery and diarrhoea have not been pharmacologically evaluated yet for their possible antidiarrhoeal properties. Twenty-three and six plants have not been evaluated pharmacologically and microbiologically, respectively. The present information may serve as a baseline data to initiate further research for discovery of new compounds and biological activities of these potential plants. Further research on these plants may provide some important clues for development of new drugs for dysentery and diarrhoea or other related diseases.     

New mescaline concentrations from 14 taxa/cultivars of Echinopsis spp. (Cactaceae) (“San Pedro”) and their relevance to shamanic practice

Aim of the study

The aim of the present study is to determine in a procedurally uniform manner the mescaline concentrations in stem tissue of 14 taxa/cultivars of the subgenus Trichocereus of the genus Echinopsis (Cactaceae) and to evaluate the relationship (if any) between mescaline concentration and actual shamanic use of these plants.

Materials and methods

Columnar cacti of the genus Echinopsis, some of which are used for diagnostic and therapeutic purposes by South American shamans in traditional medicine, were selected for analysis because they were vegetative clones of plants of documented geographic origin and/or because they were known to be used by practitioners of shamanism. Mescaline content of the cortical stem chlorenchyma of each cactus was determined by Soxhlet extraction with methanol, followed by acid-base extraction with water and dichloromethane, and high-pressure liquid chromatography (HPLC).

Results

By virtue of the consistent analytical procedures used, comparable alkaloid concentrations were obtained that facilitated the ranking of the various selected species and cultivars of Echinopsis, all of which exhibited positive mescaline contents. The range of mescaline concentrations across the 14 taxa/cultivars spanned two orders of magnitude, from 0.053% to 4.7% by dry weight.

Conclusions

The mescaline concentrations reported here largely support the hypothesis that plants with the highest mescaline concentrations - particularly E. pachanoi from Peru - are most associated with documented shamanic use.     

二对氯苯甲酰莲心碱对实验性心律失常的影响

目的　研究二对氯苯甲酰莲心碱抗心律失常的药理作用。方法　采用乌头碱、哇巴因、氯化钙 3种抗心律失常模型。结果　二对氯苯甲酰莲心碱 5mg·kg-1iv可明显提高乌头碱致大鼠、哇巴因致豚鼠发生室性早搏、室性心动过速、室颤及心脏停搏用量 ;延长氯化钙诱发大鼠心律失常的出现时间 ,减少早搏、室颤的发生率及死亡率。结论　二对氯苯甲酰莲心碱具有广泛的抗心律失常作用     

辛夷二氯甲烷提取物抗炎、抗过敏作用研究

目的：研究中药辛夷二氯甲烷提取物的药理作用。方法：采用体外,体内多种动物模型对辛夷二氯甲烷提取物进行了抗炎,抗过敏方面的研究。结果：辛夷二氯甲烷提取物对组胺（HA）、乙酰胆碱（Ach)引起的豚鼠离体回肠收缩具有显著的抑制作用,并能抑制卵白蛋白（OA）所致的豚鼠离体回肠过敏性收缩,对HAc引起的小鼠腹腔毛细血管通透性增高具有抑制作用,能显著抑制角叉菜胶引起的小鼠足肿胀,并减少前列腺素E2（PGE2）在炎症组织中产生。结论：辛夷二氯甲烷提取物具有明显的抗炎,抗过敏作用。