Characterization of 5-HT1A receptor functional coupling in cells expressing the human 5-HT1A receptor as assessed with the cytosensor microphysiometer.

The functional activity of a series of 5-HT1A receptor ligands has been evaluated in a cell line expressing the human 5-HT1A receptor (h5-HT1A x CHO) using the agonist-stimulated increase in extracellular acidification rate, measured with the microphysiometer, as a functional assay. Both 5-CT and 8-OH-DPAT were potent agonists in stimulating an increase in extracellular acidification rate in h5-HT1A x CHO cells with estimated EC50 values of 1.2 and 7.

The pharmacological profile of L-glutamate transport in human NT2 neurones is consistent with excitatory amino acid transporter 2.

The human teratocarcinoma cell line NTera2/D1 can be differentiated to produce post-mitotic neurones (NT2-N cells) by prolonged (> 3 week) exposure to retinoic acid. In this study, we describe the characterisation of high-affinity Na+-dependent L-glutamate transport activity in post-mitotic differentiated NT2-N cells. NT2-N cells, but not the undifferentiated precursor cells, transported L-glutamate in a Na+-dependent manner, as determined by equimolar replacement of Na+ with choline.

CCK receptor antagonists.

1. The peptide hormone and neurotransmitter, cholecystokinin, is widely distributed throughout the gastrointestinal tract and central nervous system and mediates a diverse number of biological functions. 2.

The cholecystokinin-B receptor antagonist L-740,093 produces an insurmountable antagonism of CCK-4 stimulated functional response in cells expressing the human CCK-B receptor.

A stable cell line expressing the human cholecystokinin-B receptor gene (hCCK-B.CHO) has been employed in an evaluation of the recently developed CCK-B receptor antagonist L-740,093. L-740,093 exhibited high affinity (IC50 0.

YM022 [(R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1,4- benzodiazepin-3-yl]-3-(3-methylphenyl)urea]: an irreversible cholecystokinin type-B receptor antagonist.

A functional evaluation of the recently developed cholecystokinin type-B (CCK-B) receptor antagonist YM022 [(R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1,4-++ +benzodiazepin-3-yl]-3-(3-methylphenyl)urea] was undertaken in Chinese hamster ovary cells stably expressing the human CCK-B receptor gene (hCCK-B.CHO). YM022 exhibited high affinity and selectivity for the CCK-B receptor subtype as estimated from [125I]CCK8S displacement studies using membranes derived from hCCK-B.

Connexin 26 mutations in hereditary non-syndromic sensorineural deafness.

Severe deafness or hearing impairment is the most prevalent inherited sensory disorder, affecting about 1 in 1,000 children. Most deafness results from peripheral auditory defects that occur as a consequence of either conductive (outer or middle ear) or sensorineuronal (cochlea) abnormalities. Although a number of mutant genes have been identified that are responsible for syndromic (multiple phenotypic disease) deafness such as Waardenburg syndrome and Usher 1B syndrome, little is known about the genetic basis of non-syndromic (single phenotypic disease) deafness.

Nuclear sites of herpes simplex virus type 1 DNA replication and transcription colocalize at early times postinfection and are largely distinct from RNA processing factors.

We have visualized the intracellular localization of herpes simplex virus (HSV) type 1 replication and transcription sites in infected HeLa cells by using direct labelling methods. The number of viral transcription foci increases in a limited way; however, the number of replication sites increases in a near-exponential manner throughout infection, and both replication and transcription sites are found buried throughout the nuclear interior. Simultaneous visualization of viral transcription and replication foci shows that the two processes colocalize at early times, but at later times postinfection, there are additional sites committed solely to replication.

Full and partial agonist activity of C-terminal cholecystokinin peptides at the cloned human CCK-A receptor expressed in Chinese hamster ovary cells.

The agonist activities of the C-terminal cholecystokinin peptides sulfated cholecystokinin octapeptide (CCK-8S), non-sulfated cholecystokinin octapeptide (CCK-8NS), pentagastrin and CCK-4 at the cloned human CCK-A receptor expressed in Chinese hamster ovary cells were evaluated in two functional assays of receptor activation. [125I]-CCK-8S displacement studies employing membranes derived from these cells revealed the expected rank order of affinity for a number of CCK receptor ligands. CCK-8S was a potent agonist in (i) stimulating the mobilization of intracellular free Ca2+, measured with the Ca2+ sensitive fluorescent indicator FURA-2, and (ii) stimulating increases in extracellular acidification rates, measured by microphysiometry.

Pharmacological characterization of a Chinese hamster ovary cell line transfected with the human CCK-B receptor gene.

A stable Chinese hamster ovary cell line expressing the human CCK-B receptor gene is described (hCCK-B.CHO). In radioligand binding experiments employing membranes derived from these cells the rank order of affinity estimated for a series of CCK receptor ligands (CCK-8S > CI988 > PD 135158 > pentagastrin > CCK-8NS > L-365,260 > CCK-4 > LY 288513 > devazepide > A71378 > lorglumide) was found to be in excellent agreement with CCK-B receptor pharmacology described in guinea-pig cortex.

Herpes simplex virus type 1 protein IE63 affects the nuclear export of virus intron-containing transcripts.

Using in situ hybridization labelling methods, we have determined that the herpes simplex virus type 1 immediate-early protein IE63 (ICP27) affects the cellular localization of virus transcripts. Intronless transcripts from the IE63, UL38, and UL44 genes are rapidly exported to and accumulate in the cytoplasm throughout infection, in either the presence or absence of IE63 expression. The intron-containing transcripts from the IE110 and UL15 genes, while initially cytoplasmic, are increasingly retained in the nucleus in distinct clumps as infection proceeds, and the clumps colocalize with the redistributed small nuclear ribonucleoprotein particles.

Immediate early protein IE63 of herpes simplex virus type 1 binds RNA directly.

The herpes simplex virus type 1 (HSV-1) immediate early protein IE63 acts post-transcriptionally to affect RNA 3'-processing and splicing. Functional domains such as the RGG box and zinc-finger motifs potentially provide the protein with RNA binding capacity. Here, IE63 protein expressed in E.

Regulation of herpes simplex virus poly (A) site usage and the action of immediate-early protein IE63 in the early-late switch.

The essential herpes simplex virus type 1 (HSV-1) immediate-early IE63 (ICP27) is pleiotropic in function, promoting the switch from the early to late phase of virus gene expression, and has effects on the posttranscriptional processes of mRNA splicing and 3' processing. We have investigated the role of IE63 in the regulation of viral mRNA 3' processing and of late gene expression. Our in vitro 3' processing studies demonstrated that HSV-1 infection induces an activity, which requires IE63 gene expression, responsible for an observed increase in 3' processing of selected HSV-1 poly(A) sites.

Epibatidine: a nicotinic acetylcholine receptor agonist releases monoaminergic neurotransmitters: in vitro and in vivo evidence in rats.

The effect of the neuronal acetylcholine-gated ion channel receptor agonist (+/-)-epibatidine was studied on neurotransmitter release in vitro and motor behavior in vivo. (+/-)-Epibatidine (3-300 nM) caused a concentration- and calcium-dependent release of [3H]-dopamine from striatal slices and [3H]-norepinephrine release from hippocampal and thalamic slices. (+/-)-Epibatidine-induced neurotransmitter release was inhibited in all three regions by mecamylamine (3 microM).

Membrane insertion and assembly of ductin: a polytopic channel with dual orientations.

Ductin is a highly conserved and polytopic transmembrane protein which is the subunit c component of the vacuolar H(+)-ATPase (V-ATPase) and a component of a connexon channel of gap junctions. Previous studies have suggested that ductin in the V-ATPase has the opposite orientation of ductin in a connexon. Using an in vitro translation system coupled to microsomes derived from the endoplasmic reticulum, we show that ductin is co-translationally inserted into the membrane bilayer, suggesting a dependency on the signal recognition particle for synthesis.

Pharmacological characterization of neuronal acetylcholine gated ion channel receptor-mediated hippocampal norepinephrine and striatal dopamine release from rat brain slices.

Neuronal acetylcholine-gated ion channel receptor-mediated [3H]-norepinephrine ([3H]-NE) and [3H]-dopamine ([3H]-DA) release from rat hippocampal and striatal slices, respectively, were compared. The nicotinic receptor agonists (-)-nicotine, (-)-cytisine and 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP) increased both [3H]-NE and [3H]-DA release in a concentration-dependent manner. The rank order of potency for the three agonists was DMPP > (-)-cytisine > (-)-nicotine for evoking [3H]-NE release and (-)-cytisine > DMPP = (-)-nicotine for releasing [3H]-DA.

Will the Russians return from the near abroad?

The author "examines a range of issues surrounding the involuntary migration of Russian populations from the non-Russian republics of the former USSR. Among the questions addressed are possible magnitudes of in-migration into Russia (with special attention paid to conditions in one of the major source regions, Central Asia), attitudes in Russia regarding appropriate policy with respect to treatment of co-nationals in the near abroad and whether their return to Russia would have a positive or negative impact, and conditions in areas of Russia that presently are absorbing the greatest numbers of migrants. The assertion that Russian policy should seek aggressively to prevent the out-migration of Russian populations [from] the near abroad is assessed critically.

L-trans-pyrrolidine-2,4-dicarboxylate and cis-1-aminocyclobutane-1,3-dicarboxylate behave as transportable, competitive inhibitors of the high-affinity glutamate transporters.

The ability of two conformationally restricted analogues of L-glutamate to function as non-transportable inhibitors of plasma membrane L-glutamate transport was investigated in primary cultures of cerebellar granule cells and cortical astrocytes. L-trans-Pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC) and cis-1-aminocyclobutane-1,3-dicarboxylic acid (cis-ACBD) behaved as linear competitive inhibitors of the uptake of D-[3H]aspartate (used as a non-metabolizable analogue of L-glutamate) exhibiting Ki values between 40 and 145 microM; L-trans-PDC being the more potent inhibitor in each preparation. However, both L-trans-PDC and cis-ACBD, over a concentration range of 1 microM-5 mM, dose-dependently stimulated the release of exogenously supplied D-[3H]aspartate from granule cells maintained in a continuous superfusion system.