Promotion of spermatogonial proliferation by neuregulin 1 in newt (Cynops pyrrhogaster) testis.

We have previously shown that mammalian follicle-stimulating hormone (FSH) promotes the proliferation of spermatogonia and their differentiation into primary spermatocytes in organ culture of newt testis. In the current study, we performed microarray analysis to isolate local factors secreted from somatic cells upon FSH treatment and acting on the germ cells. We identified neuregulin 1 (NRG1) as a novel FSH-upregulated clone homologous to mouse NRG1 known to control cell proliferation, differentiation and survival in various tissues.

Local anesthetics have different mechanisms and sites of action at recombinant 5-HT3 receptors.

Background And Objectives: In addition to their blockade of voltage-dependent sodium channels, the action of local anesthetics at 5-hydroxytryptamine-3 (5-HT3) receptors may be clinically relevant. Because local anesthetics have different clinical properties, we have tested the hypothesis that differences in interactions at the 5-HT3 receptor may be clinically relevant by investigating the effects of 4 local anesthetics on recombinant wild-type and 4 mutant 5-HT3A receptors.

Methods: The cRNAs from human wild-type and 4 mutant 5-HT3A subunit clones were synthesized in vitro and expressed in Xenopus oocytes.

Size-selective junctional barrier and Ca(2+)-independent cell adhesion in the testis of Cynops pyrrhogaster: expression and function of occludin.

In urodeles which has testicular structure different from that in mammals, blood-testis barrier was reported to exist like in mammals. However, molecular and functional analyses of the components of the blood-testis barrier in urodeles have not been reported yet. Toward elucidation of the barrier functions and their molecular components in newt testis, we aimed to isolate occludin cDNAs and obtained two kinds of occludin partial cDNAs (occludin 1 and 2) encoding the putative second extracellular loop.

Two types of GABAergic miniature inhibitory postsynaptic currents in mouse substantia gelatinosa neurons.

The physiological and pharmacological properties of gamma-aminobutyric acid (GABA)ergic miniature inhibitory postsynaptic currents (mIPSCs) were investigated in substantia gelatinosa neurons of mouse spinal cord using whole-cell patch clamp recordings. Two cell populations were pharmacologically identified based on the effect of propofol (10 muM) on the mIPSC decay kinetics: those exhibiting propofol-sensitive mIPSCs, with a slow decay kinetic (mIPSC(SLOW)), and those exhibiting propofol-resistant mIPSCs, with a fast decay kinetic (mIPSC(FAST)) (decay time constants of 14.2+/-0.

GABAergic tonic inhibition of substantia gelatinosa neurons in mouse spinal cord.

We used whole-cell recording to identify, for the first time, GABAergic tonic current in subpopulations of substantia gelatinosa neurons in mouse spinal cord slices. Application of the gamma-aminobutyric acid type A receptor antagonist bicuculline revealed tonic currents in 49 of 73 substantia gelatinosa neurons. These tonic currents were dissected into three groups according to their diverse pharmacological properties.

[Adsorption of local anesthetic into disposable infusion balloon].

Background: The aim of this study was to investigate the adsorption of local anesthetics lidocaine and ropivacaine, into disposable infusion balloons made from various kinds of plastics.

Methods: The concentration of local anesthetic that flows out of a balloon was measured.

Results: The concentration of both lidocaine and ropivacaine in clinical formula decreased only 4.

In vitro antagonism of recombinant ligand-gated ion-channel receptors by stereospecific enantiomers of bupivacaine.

Background And Objectives: Bupivacaine is a racemic mixture of S(-)- and R(+)-enantiomers. Both isomers have similar potency as local anesthetics, but the S(-)-enantiomer produces less central nervous system and cardiovascular toxicity. Local anesthetic-induced convulsion is likely to be associated with not only sodium channel but also ligand-gated ion channel.

Sorptive loss of volatile and gaseous anesthetics from in vitro drug application systems.

In in vitro pharmacological experiments, determination of effective concentration values for various anesthetics depends on understanding the exact concentration of the drugs dissolved in physiological solutions. Actual anesthetic concentration may differ from expectations because of drug adsorption, absorption or other loss, especially in tubing. We tested the hypothesis that delivered concentrations of anesthetics decrease when solutions pass through laboratory tubing and investigated such loss by measuring the entering and exiting dissolved concentrations of two volatile (sevoflurane and isoflurane) and two gaseous (nitrous oxide and xenon) anesthetics.

Mapping of putative ether-anesthesia resistance gene using C57BL/6J and MSM/Ms mouse strains.

Purpose: We attempted to identify the locations of major mouse genes responsible for sensitivity to diethylether (ether) anesthesia, using microsatellite linkage analyses including Quantitative Trait Locus (QTL) analysis.

Methods: To determine the locations of ether anesthesia resistance genes on chromosomes, an ether anesthesia-resistant mouse strain, C57BL/6J (C57BL), and an ether anesthesia-sensitive mouse strain, MSM/Ms (MSM), were used. The sensitivity of mice to ether anesthesia was determined from the latency time required to lose the righting reflex during exposure to 4% ether vapor in air.

Inhibitory effect of glucocorticoids on human-cloned 5-hydroxytryptamine3A receptor expressed in xenopus oocytes.

Background: Methylprednisolone, dexamethasone, and other glucocorticoids have been found effective against nausea and vomiting induced by chemotherapy and surgery. Although the specific 5-hydroxytriptamine3 (5-HT3) receptor antagonists such as ondansetron and ramosetron are used as antiemetics, reports show that the use of 5-HT3 receptor antagonists with some glucocorticoids brings additional effects. Glucocorticoids are reported to be antiemetic.

Xenon suppresses nociceptive reflex in newborn rat spinal cord in vitro; comparison with nitrous oxide.

Although analgesic action of xenon has been reported, little is known about the effect of xenon at the spinal cord, which plays a crucial role in nociceptive transmission. We studied the effect of xenon on nociceptive reflex (the slow ventral root potential) and the monosynaptic reflex in neonatal rat spinal cord in vitro in comparison with nitrous oxide. Xenon (30%) and nitrous oxide (30%) were applied for 17 min through superfusing artificial cerebrospinal fluid.

In vitro inhibition of recombinant ligand-gated ion channels by high concentrations of milnacipran.

Rationale: Tricyclic antidepressants are known to inhibit various ligand-gated ion-channel (LGIC) receptors, and some of their clinical features may be associated with this activity. The effects of milnacipran, a selective inhibitor of the reuptake of serotonin and noradrenaline, on LGIC receptors have not yet been investigated on such ion-channel receptors.

Objectives: To determine the in vitro effect of milnacipran on four recombinant LGIC receptors, nicotinic acetylcholine, N-methyl-D-aspartate, gamma-amino butyric acid (GABA) and 5-hydroxytryptamine3A receptors.

Evidence for the involvement of GABA(A) receptor blockade in convulsions induced by cephalosporins.

There is accumulating evidence that most beta-lactam antibiotics (i.e., cephalosporins and penicillins) have some degree of convulsive activity, both in laboratory animals as well as in clinical settings.

Local anaesthetics have different mechanisms and sites of action at the recombinant N-methyl-D-aspartate (NMDA) receptors.

(1) Although the principal pharmacological targets of local anaesthetics (LAs) are voltage-gated Na(+) channels, other targets have also been suggested. Here we examined the effects of LAs on the N-methyl-D-aspartate (NMDA) receptor, a receptor involved in the process of nociception. (2) LAs (bupivacaine, lidocaine, procaine, and tetracaine) reversibly and concentration-dependently inhibited recombinant epsilon1/zeta1 and epsilon2/zeta1 NMDA receptors expressed in Xenopus oocytes (IC(50)s for bupivacaine, lidocaine, procaine, and tetracaine were 1032.

Nitrous oxide and xenon inhibit the human (alpha 7)5 nicotinic acetylcholine receptor expressed in Xenopus oocyte.

The neuronal nicotinic acetylcholine (nACh) receptor is one of the ligand-gated ion channels that regulate the synaptic release of neurotransmitters in the central nervous system. Recently, neuronal nACh receptors have received attention as a potential target for general anesthetics because many general anesthetics inhibit their functions at clinical concentrations. Several general anesthetics are known to inhibit the homomeric (alpha(7))(5) nACh receptor, a subtype of neuronal nACh receptors, but the effects of two gaseous anesthetics, nitrous oxide (N(2)O) and xenon (Xe), remain unknown.

Intracerebroventricular injection of the antibiotic cefoselis produces convulsion in mice via inhibition of GABA receptors.

A majority of beta-lactam antibiotics (e.g., cephalosporins and penicillins) have convulsive activity to a greater or lesser extent.

The diverse actions of volatile and gaseous anesthetics on human-cloned 5-hydroxytryptamine3 receptors expressed in Xenopus oocytes.

Background: General anesthetics can modulate the 5-hydroxytryptamine type 3 (5-HT3) receptor, which may be involved in processes mediating nausea and vomiting, and peripheral nociception. The effects of the new volatile anesthetic sevoflurane and the gaseous anesthetics nitrous oxide (N2O) and xenon (Xe) on the 5-HT3 receptor have not been well-characterized.

Methods: Homomeric human-cloned 5-HT3A receptors were expressed in Xenopus oocytes.

The beta-lactam antibiotics, penicillin-G and cefoselis have different mechanisms and sites of action at GABA(A) receptors.

The action of the beta-lactam antibiotics, penicillin-G (PCG) and cefoselis (CFSL) on GABA(A) receptors (GABA(A)-R) was investigated using the two-electrode voltage clamp technique and Xenopus oocyte expressed murine GABA(A)-R. Murine GABA(A)-Rs were expressed in Xenopus oocytes by injecting cRNA that encoded for each subunit (alpha1, beta2, and gamma2) and the effects of PCG and CFSL on the alpha1beta2gamma2s subunit receptors were examined using two-electrode voltage clamp. Using the alpha1beta2gamma2s GABA(A)-R, PCG and CFSL inhibited GABA-induced currents in a concentration-dependent manner, with IC(50)s of 557.