Selective blockers of the norepinephrine transporter (NET) inhibit dopamine uptake in the prefrontal cortex. This suggests that dopamine in this region is normally cleared by the somewhat promiscuous NET. We have tested this hypothesis by comparing the effects of inhibitors selective for the three monoamine transporters with those of a nonspecific inhibitor, cocaine, on uptake of 3H-dopamine into synaptosomes from frontal cortex, caudate nucleus, and nucleus accumbens from wild-type, NET, and dopamine transporter (DAT) knock-out mice. Dopamine uptake was inhibited by cocaine and nisoxetine, but not by GBR12909, in frontal cortex synaptosomes from wild-type or DAT knock-out mice. At transporter-specific concentrations, nisoxetine and GBR12909 failed to block dopamine uptake into frontal cortex synaptosomes from NET knock-out mice. The efficacy of cocaine at the highest dose (1 mm) was normal in DAT knock-out mice but reduced by 70% in NET knock-out mice. Nisoxetine inhibited dopamine uptake by 20% in caudate and nucleus accumbens synaptosomes from wild-type and DAT knock-out mice but had no effect in those from NET knock-out mice. Cocaine failed to block dopamine uptake into caudate or nucleus accumbens synaptosomes from DAT knock-out mice. Cocaine and GBR12909 each inhibited dopamine uptake into caudate synaptosomes from NET knock-out mice, but cocaine effectiveness was reduced in the case of nucleus accumbens synaptosomes. Thus, whereas dopamine uptake in caudate and nucleus accumbens depends primarily on the DAT, dopamine uptake in frontal cortex depends primarily on the NET. These data underscore the fact that which transporter clears dopamine from a given region depends on both the affinities and the local densities of the transporters.

Hepatitis E virus (HEV) RNA replication occurred in seven of nine primate cell cultures transfected with in vitro transcripts of an infectious cDNA clone. Cell-to-cell spread did not occur in cell cultures, but rhesus monkeys inoculated with lysates of HEV-transfected PLC/PRF/5 and Huh-7 cells became infected with HEV. A replicon with the ORF2 and ORF3 genes deleted and replaced with the green fluorescent protein gene also replicated in the same primate cells that supported the replication of the full-length genome. Fluorescenceactivated cell sorter analysis confirmed that the 7mG cap structure was critical for efficient infectivity, although replication could be initiated at a very low level in its absence. HEV virions were also able to infect a limited number of cells of certain lines.Hepatitis E virus (HEV), the prototype Hepevirus, and hepatitis A virus (HAV) together are the major etiological agents of enterically transmitted hepatitis (4,8,23). HEV has a higher mortality rate, especially in pregnant women, but the reason for this is unknown. Otherwise, the disease caused by the one virus is clinically indistinguishable from that caused by the other, and neither progresses to chronicity. Both viruses have nonenveloped capsids, and both contain a single stranded RNA genome of the positive sense which serves as an mRNA to initiate infection.In spite of the similarities, HEV and HAV have very different epidemiologies. HAV age-related seroprevalence patterns are those expected for a virus that is transmitted by the fecaloral route, whereas those of HEV are not, even though fecal contamination is the major source of transmission. In countries in which the virus is endemic, anti-HAV antibodies are generally acquired before the age of 5 years, whereas the major rise in anti-HEV seroprevalence occurs later, in young adults (3). HAV has been found only in humans and in some nonhuman primates. HEV, on the other hand, has been isolated from humans and swine (7,9,20): additionally, antibodies reactive with capsid protein from human strains of HEV have been found in many animals, including nonhuman primates (2) and multiple species of rodents including rats (6, 11). A genotype 3 strain of HEV naturally infecting swine has been passed experimentally to monkeys, and a genotype 3 strain infecting humans has been passed to swine (18). However, attempts to transmit other human strains to swine have failed (19). The question of whether HEV is a zoonosis is still open (17), but a recent cluster of hepatitis E cases in Japan was traced to ingestion of raw deer meat, suggesting that this may be the case (26).The molecular biology of HEV replication is not well un- Much of the scant knowledge concerning HEV at the molecular level has been obtained through the overexpression of recombinant proteins in vitro. In addition to identification of an active viral RNA-dependent RNA polymerase, (1), such studies have led to the demonstration of guanylyltransferase and methyltransferase activities (15), two enzymatic activities required to ...

Combined administration of the amphetamine analogs phentermine and fenfluramine (PHEN/FEN) has been used in the treatment of obesity. While these medications are thought to modulate monoamine transmission, the precise neurochemical effects of the PHEN/FEN mixture have not been extensively studied. To assess the mechanism of PHEN/FEN action, in vivo microdialysis studies were performed in the nucleus accumbens of conscious freely moving rats. A series of amphetamine derivatives including phentermine, chlorphentermine, fenfluramine, and PHEN/FEN (1:1 ratio), were infused locally into the accumbens via reverse-dialysis (1, 10, 100 microM) or injected systemically (1 mg/kg, ip). Dialysate samples were assayed for dopamine (DA) and serotonin (5-HT) by high-performance liquid chromatography with electrochemical detection. When infused locally, phentermine preferentially increased extracellular DA, whereas fenfluramine selectively increased extracellular 5-HT. Local administration of chlorphentermine or the PHEN/FEN mixture caused parallel elevations of both transmitters. Analogous results were obtained when the drugs were injected systemically. Phentermine stimulated robust locomotor activity in mice, whereas chlorphentermine and fenfluramine did not. PHEN/FEN caused modest locomotor stimulation after a low dose, but had no effect at the highest dose. Accumulating evidence suggests that chronic drug and alcohol abuse is associated with deficits in both DA and 5-HT neuronal function. Thus, dual activation of DA and 5-HT neurotransmission with monoamine releasing agents may be an effective treatment strategy for substance use disorders, as well as for obesity. Synapse 36:102-113, 2000. Published 2000 Wiley-Liss, Inc.

Fourteen different chimeric virus genomes were constructed from two infectious cDNA clones encoding a virulent and an attenuated isolate, respectively, of the HM175 strain of hepatitis A virus. The ability of each recombinant virus to infect tamarins and to cause acute hepatitis was determined. Comparisons of the genotype and phenotype of each virus suggested that VP1/2A and 2C genes were responsible for virulence. The 2C gene derived from the attenuated parent virus was unstable, and one or more mutations arose in this gene during the first passage in tamarins.