Correlation between 5-HT7 receptor affinity and protection against sound-induced seizures in DBA/2J mice

Audiogenic seizures can be induced in DBA/2J mice following intense auditory stimulation. A number of neurotransmitters, including 5-hydroxytryptamine (5-HT), are believed to be involved in mediating this effect since it has been shown previously that depletion of 5-HT or blockade of 5-HT receptors protects DBA/2J mice from these audiogenic seizures. The present study was undertaken to determine whether antagonism of the newly identified 5-HT₇ receptor may protect DBA/2J mice from audiogenic seizures by attempting to correlate in vivo potency of compounds with their affinity at the 5-HT₇ receptor. All compounds used in the correlation were shown to be antagonists at the 5-HT₇ receptor and a statistically significant correlation was observed between 5-HT₇ affinity and doses for half-maximal response (ED₅₀) for protection of DBA/2J mice from sound-induced seizures (r = 0.80; P < 0.05). No significant correlation was observed between in vivo activity and affinity at either 5-HT_1A, 5-HT_2A or 5-HT_2C receptors. It is also unlikely that interactions between the 5-ht₅ receptor will protect DBA/2J mice from audiogenic seizures since metergoline and mesulergine which are both active in this in vivo model have no affinity for the 5-ht₅ receptor. There are similarities between the pharmacology of the 5-HT₇ receptor and that of the 5-HT_1A receptor, however the correlation between the in vivo potency in DBA/2J mice and 5-HT_1A affinity was not significant. Furthermore, the 5-HT_1A receptor antagonist WAY 100135 did not protect DBA/2J mice from audiogenic seizures at doses that antagonise 5-HT_1A receptor-mediated effects in mice. These data suggest that antagonism of 5-HT₇ receptors may protect against audiogenic seizures in DBA/2J mice although a definitive conclusion must await studies with selective 5-HT₇ antagonists. Received: 20 March 1997 / Accepted: 10 August 1997     

Expression of the c-erbB-2-encoded oncoprotein and progesterone receptor in human meningiomas

The present study investigated the expression of c-erbB-2 in 59 meningiomas, including different histological subtypes and anaplastic variants, by immunocytochemistry and molecular biological techniques. Immunohistochemistry using the monoclonal antibody FWP-51 directed against c-erbB-2-encoded oncoprotein gp185 demonstrated variable degrees of immunoreactivity in all meningiomas. The intensity of immunostaining correlated with the degree of expression as assessed by Western analysis in 28 meningiomas using polyclonal antiserum 21N. There was no correlation between the degree of expression and histological variants. Immunoreactivity of all menigiomas was distinctly less intense, however, than that of the human breast cancer cell line SK-BR-3, and slightly lower than that of brain metastases of breast and ovarian carcinomas that served as positive controls for both methods. By Southern analysis all meningiomas showed a single copy of the c-erbB-2 gene. Non-neoplastic arachnoid cap cells also exhibited c-erbB-2 expression and the degree of immunoreactivity was comparable with the majority of meningiomas. These data argue against an overexpression of c-erbB-2 in meningiomas, but rather indicate a cell-type-specific constitutive expression of the c-erbB-2 gene product in meningiomas and their putative progenitor cells. Since a subgroup of meningiomas is known to express progesterone receptors (PR), gp185 immunoreactivity was compared to the hormone receptor status using monoclonal antibody KD68. Fifty-six percent meningiomas showed PR immunoreactivity, but there was no statistically significant correlation with the degree of gp185 expression.This study was supported by a grant of the Tumorzentrum Heidelberg/Mannheim (M.K., No. 10028060)     

Pharmacokinetics of the 13C labeled anticancer agent temozolomide detected in vivo by selective cross-polarization transfer

The anticancer agent temozolomide labeled with ¹³C (8-Carbamoyl-3-13C-methylimidazo-[5,1-d]-1,2,3,5-tetrazin-4-(3H)-one), was noninvasively detected in subcutaneous RIF-1 tumors by a selective cross polarization ¹³C NMR method, at a field strength of 9.4T. Pharmacokinetics of the drug, at a dose of 150 mg/kg, were determined for intravenous and intraperitoneal modes of administration (three animals per mode). The half-life of the drug in the tumors was approximately 60 min. The uptake and clearance of the drug, however, varied significantly between individual hosts, for both modes of administration. These results demonstrate the feasibility of obtaining pharmacokinetics of anticancer agents for individual tumors without the need for a label that might modify drug activity (e.g., fluorine). The variability of the in vivo measurements, even within the same tumor model, demonstrates the necessity of directly monitoring the tumor to evaluate drug pharmacokinetics.     

Differential inhibition of cyclooxygenase-1 (COX-1) and-2 (COX-2) by NSAIDS: Consequences on anti-inflammatory activity versus gastric and renal safety

The discovery of an inducible isoform of cyclooxygenase (COX-2) requires a refinement of the theory that inhibition of cyclooxygenase activity is responsible for both therapeutic and side-effects of nonsteroidal anti-inflammatory drugs (NSAIDs). Pharmacological results with developmental compounds suggest that COX-2 is the relevant target for the therapeutic (i.e. anti-inflammatory) effects of NSAIDs, whereas gastric and renal side-effects are related to inhibition of constitutive COX-1. However a role of COX-1 in inflammation cannot be excluded. Furthermore, more research effort is needed to investigate the functional relevance of COX-2 in normal tissue.     

Does H2-receptor antagonist alter the renal function of cyclosporine-treated kidney grafts?

Histamine-type 2 antagonists (H₂-blockers) as represented by cimentidine have been shown to adversely affect renal allograft function, particularly when coadministered with cyclosporine, currently a major immunosuppressant. To determine whether or not a newer and more powerful H₂-blocker, famotidine, would produce similar adverse effects, we assessed seven cyclosporine-treated renal allograft recipients with regard to changes in their renal function on or off the H₂-blocker over a one-week period. Neither the administration nor withdrawal of famotidine (20–40 mg/day) resulted in any significant changes in serum creatine, BUN, urine output or cyclosporine trough levels, suggesting that famotidine can be safely administered as an H₂-blocker to cyclosporine-treated renal allograft recipients.     

钙拮抗剂TMB-8抑制BHQ,NE和KCl引起的培养乳牛基底动脉单个平滑肌细胞内游离钙的升高

用AR CM MIC阳离子测定系统,测量单个细胞内游离钙浓度([Ca²⁺]i),研究8-(N,N-二乙胺)-n-辛基 3,4,5-三甲氧基苯甲酸酯(TMB-8)对培养乳牛基底动脉平滑肌[Ca²⁺]i的作用。在细胞外钙浓度为1.3mmol·L^-1时,TMB-8(30μmol·L^-1)可明显抑制BHQ,NE及KCl引起[Ca²⁺]i的升高。在细胞外钙为零+EGTA 0.1mmol·L^-1时,TMB-8(10,30及100μmol·L^-1)可浓度依赖性地降低静息[Ca²⁺]i,TMB-8(30μmol·L^-1)可几乎完全阻断BHQ及NE引起[Ca²⁺]i的增加。研究表明TMB-8降低培养乳牛基底动脉平滑肌[Ca²⁺]i的机制,主要是抑制肌浆网Ca²⁺的释放,或增加肌浆网对Ca²⁺的摄入,并由此间接地抑制细胞外钙的内流。     

EFFECTS OF BKCa CHANNELS ON THE REDUCTION OF CYTOSOLIC Ca2+ IN cGMP-INDUCED RELAXATION OF GUINEAPIG TRACHEA

1. In order to examine the mechanisms of cGMP-induced relaxation in airway smooth muscle, the effects of atrial natriuretic peptide (ANP) and 8-brom cGMP on muscle tone were studied by measuring isometric tension, while the effects on cytosolic Ca²⁺ concentrations were studied by measuring the spectra of fura-2 loaded in guinea-pig tracheal strips. 2. Atrial natriuretic peptide and 8-brom cGMP caused a concentration-dependent inhibition of spontaneous tone in the guinea-pig trachea. The relaxant effects of these agents on spontaneous tone were markedly suppressed in the presence of iberiotoxin (IbTX), a selective inhibitor of large-conductance Ca²⁺-activated K⁺ (BKca) channels. Iberiotoxin (30 nmol/L) markedly affected the maximal effect induced by ANP and 8-brom cGMP and augmented EC₇₀ values for ANP and EC₅₀values for 8-brom cGMP approximately 27- and 17-fold, respectively. The inhibitory effects of IbTX on relaxation induced by these agents were diminished in the presence of 1 μmol/L nifedipine, an antagonist of voltage-operated Ca²⁺channels (VOCC). 3. The inhibitory action of ANP and 8-brom cGMP on spontaneous tone was not affected by the presence of 10 μmol/L glibenclamide, an inhibitor of ATP-sensitive K⁺ channels, and 100 nmol/L apamin, an inhibitor of small-conductance Ca²+-activated K⁺ channels. When these agents were applied to tissues precontracted by high (40mmol/L) K⁺, the relaxant effects of these agents markedly diminished. 4. The extracellular Ca²⁺-dependent contraction was inhibited in the presence of 0.3 μmoI/L ANP or 0.1 mmol/L 8-brom cGMP. Concentration—response curves to extracellular Ca²⁺ (0.03—2.4 mmol/L) were markedly diminished by exposure to these agents. The maximal effect induced by extracellular Ca²⁺ was affected by these agents. 5. Atrial natriuretic peptide caused an inhibition of spontaneous tone accompanied by a reduction in the intracellular Ca²⁺ concentration. In the presence of IbTX, the elimination of both muscle tone and cytosolic Ca²⁺ by ANP was suppressed. 6. We conclude that ANP and 8-brom cGMP activate BKca channels and that the inhibition of Ca²⁺ influx through VOCC, mediated by BKca channel activation, may be involved in cGMP-dependent bronchodilation.     

单波长荧光分光光度计测定细胞内Ca^2＋浓度的方法探索

在使用单波长荧光分光光度计测定细胞内游离钙浓度时，通过快速（４～６ｓ）手动转换激发波长（ＥＸ），分别测定ＥＸ３４０和３８０ｎｍ时的荧光强度变化，并计算出３４０ｎｍ与３８０ｎｍ时的荧光强度比率（Ｒ），然后也采用双波长荧光分光光度计测定细胞内Ｃａ２＋浓度的计算公式计算细胞内游离钙浓度。结果显示单波长荧光分光光度计按比例法测得的细胞内游离Ｃａ２＋浓度与使用双波长荧光分光光度计测得的结果相似。     

Pharmacological properties of Ca2+-activated K+ currents of ramified murine brain macrophages

Using the whole-cell configuration of the patch clamp technique, calcium-activated potassium currents (I_K,Ca) were investigated in ramified murine brain macrophages. In order to induce I_K,Ca the intracellular concentration of nominal free Ca²⁺ was adjusted to 1μM. The Ca²⁺-activated K⁺ current of brain macrophages did not show any voltage dependence at test potentials between –120 and +30mV. A tenfold change in extracellular K⁺ concentration shifted the reversal potential of I_K,Ca by 51mV. The bee venom toxin apamin applied at concentrations of up to 1μM did not affect I_K,Ca. Ca²⁺-activated K⁺ currents of ramified brain macrophages were highly sensitive to extracellularly applied charybdotoxin (CTX). The half-maximal effective concentration of CTX was calculated to be 4.3nM. In contrast to CTX, the scorpion toxin kaliotoxin did not inhibit I_K,Ca at concentrations between 1 and 50nM. Tetraethylammonium (TEA) blocked 8.0% of I_K,Ca at a concentration of 1mM, whereas 31.4% of current was blocked by 10mM TEA. Several inorganic polyvalent cations were tested at a concentration of 2mM for their ability to block I_K,Ca. La³⁺ reduced I_K,Ca by 72.8%, whereas Cd²⁺ decreased I_K,Ca by 17.4%; in contrast, Ni²⁺ did not have any effect on I_K,Ca. Ba²⁺ applied at a concentration of 1mM reduced I_K,Ca voltage-dependently at hyperpolarizing potentials. Received: 17 January / Accepted: 5 May 1997     

Marital Functioning in Early Versus Late-Onset Alcoholic Couples

Current knowledge about alcohol and marital functioning is limited by restrictive sample selection, inattention to the literature on individual-based alcoholic subtypes, and lack of research linking individual differences among alcoholics to marital functioning. The present study was designed to study marital functioning of alcoholics in light of current alcohol typologies. Subjects were part of a larger study on conjoint treatment of alcoholic males and their female partners. Four typologies—including Type 1/2, In-Home/Out-of-home, SteadyIEpisodic, and EarlyILate Onset—were tested for replicability and discriminant validity before linking them to marital functioning. Discriminant validity was found only for the Early (59%)-versus Late (41 %)-Onset typology; thus, further analyses linked only this typology with marital functioning. At baseline, Early-Onset couples reported more marital instability, and the females in these couples were more distressed. During treatment, Early-Onset couples reported higher daily marital satisfaction than Late-Onset couples. Regardless of age of onset, males reported higher marital satisfaction than their spouses during treatment, but their satisfaction did not increase during treatment. Female partners' marital satisfaction increased during treatment. Female partners of Late-Onset males reported particularly low marital satisfaction during treatment. Parsing the sample according to the early-/late-onset typology yielded different predictors of marital satisfaction for males and females within each subtype. For female partners of Early-Onset alcoholics, psychological distress unrelated to her pattner's drinking severity was most associated with her own marital satisfaction, whereas marital adjustment of female partners of Late-Onset alcoholics was most associated with the male's level of perceptual accuracy regarding her needs. This pattern was reversed for the males; marital adjustment of Early-Onset alcoholics was most associated with his partner's perceptual accuracy of his needs, whereas marital functioning of Late-Onset alcoholics was best accounted for by his own psychological distress.