Preclinical and clinical evidence suggest an association between alcoholism and the primary regulator of extracellular dopamine concentrations, the dopamine transporter (DAT). However, the nature of this association is unclear. We determined if ten days of voluntary alcohol self-administration followed by withdrawal could directly alter DAT function, or if genetically-mediated changes in DAT function and/or availability could influence vulnerability to alcohol abuse. Heterozygous (DAT+/-) and homozygous mutant (DAT-/-) and wildtype (DAT+/+) mice were allowed to consume 5% alcohol in a schedule-induced polydipsia (SIP) task. In vivo fixed potential amperometry in anesthetized mice was used to (1) identify functional characteristics of mesoaccumbens dopamine neurons related to genotype, including dopamine autoreceptor (DAR) sensitivity, DAT efficiency, and DAT capacity, (2) determine if any of these characteristics correlated with alcohol drinking observed in DAT+/+ and DAT+/- animals, and (3) determine if SIP-alcohol self-administration altered DAR sensitivity, DAT efficiency, and DAT capacity by comparing these characteristics in wildtype (DAT+/+) mice that were SIP-alcohol naïve, with those that had undergone SIP-alcohol testing. DAT-/- mice consumed significantly less alcohol during testing and this behavioral difference was related to significant differences in DAR sensitivity, DAT efficiency, and DAT capacity. These functional characteristics were correlated to varying degrees with g/kg alcohol consumption in DAT+/+ and DAT+/- mice. DAR sensitivity was consistently reduced and DAT efficiency was enhanced in SIP-alcohol experienced DAT+/+ mice in comparison to naïve animals. These results indicate that DAR sensitivity is reduced by SIP-alcohol consumption and that DAT efficiency is modified by genotype as well as SIP-alcohol exposure. DAT capacity appeared to be strictly associated with SIP-alcohol consumption.

Sensitivity to pain is widely variable, and much of this variability is genetic in origin. The specific genes responsible have begun to be identified, but only for thermal nociception. In order to facilitate the identification of polymorphic, pain-related genes with more clinical relevance, we performed quantitative trait locus (QTL) mapping studies of the most common assay of inflammatory nociception, the formalin test. QTL mapping is a technique that exploits naturally occurring variability among inbred strains for the identification of genomic locations containing genes contributing to that variability. An F2 intercross was constructed using inbred A/J and C57BL/6J mice as progenitors, strains previously shown to display resistance and sensitivity, respectively, to formalin-induced nociception. Following phenotypic testing (5% formalin, 25 microl intraplantar injection), mice were genotyped at 90 microsatellite markers spanning the genome. We provide evidence for two statistically significant formalin test QTLs - chromosomal regions whose inheritance is associated with trait variability - on distal mouse chromosomes 9 and 10. Identification of the genes underlying these QTLs may illuminate the basis of individual differences in inflammatory pain, and lead to novel analgesic treatment strategies.

In vivo intoxication with Bordetella pertussis toxin (PTX) elicits a variety of physiological responses including a marked leukocytosis, disruption of glucose regulation, adjuvant activity, alterations in vascular function, hypersensitivity to vasoactive agents, and death. We recently identified Bphs, the locus controlling PTX-induced hypersensitivity to the vasoactive amine histamine, as the histamine H 1 receptor (Hrh1). In this study Bphs congenic mice and mice with a disrupted Hrh1 gene were used to examine the role of Bphs/Hrh1 in the genetic control of susceptibility to a number of phenotypes elicited following in vivo intoxication. We report that the contribution of Bphs/Hrh1 to the overall genetic control of responsiveness to PTX is restricted to susceptibility to histamine hypersensitivity and enhancement of antigen-specific delayed-type hypersensitivity responses. Furthermore, the genetic contribution of Bphs/Hrh1 to vasoactive amine sensitization is specific for histamine, since hypersensitivity to serotonin was unaffected by Bphs/Hrh1. Bphs/Hrh1 also did not significantly influence susceptibility to the lethal effects, the leukocytosis response, disruption of glucose regulation, and histamineindependent increases in vascular permeability associated with in vivo intoxication. Nevertheless, significant interstrain differences in susceptibility to the lethal effects of PTX and leukocytosis response were observed. These results indicate that the phenotypic variation in responsiveness to PTX reflects the genetic control of distinct intermediate phenotypes rather than allelic variation in genes controlling overall susceptibility to intoxication.Pertussis toxin (PTX) is a major virulence factor of Bordetella pertussis, the causative agent of whooping cough (9). The holotoxin is a hexameric protein that conforms to the A/B model of bacterial exotoxins (31). The A subunit is an ADPribosyltransferase which affects signal transduction by ribosylation of the ␣ subunit of trimeric Gi proteins while the B oligomer binds cell surface receptors on a variety of mammalian cells (19,31). PTX, when administered in vivo, elicits a large number of physiological responses including disruption of glucose regulation, leukocytosis, adjuvant activity, increased vascular permeability associated with alteration of blood-tissue barrier functions, sensitization to vasoactive agents, and death (12,24,27,29,44).Inbred strains of mice differ in susceptibility to vasoactive amine challenge following PTX sensitization in that genetically susceptible strains die from hypotensive and hypovolemic shock whereas resistant strains do not (29,43). Bphs, the gene controlling susceptibility to PTX-induced hypersensitivity to histamine, was previously mapped to the central region of mouse chromosome 6 (39) and recently identified as being the histamine H 1 receptor (Hrh1) (25). As the first step in positionally cloning Bphs, we generated a panel of interval-specific recombinant congenic lines by using marker-assisted selection to introgress the ...

In addition to reducing alcohol drinking, both drugs had other behavioral effects that included reductions in regulatory drinking. These results suggest that the therapeutic utility of these drugs for ameliorating human alcohol addiction remains questionable.

Day 3 thymectomy (D3Tx) leads to a paucity of CD4+CD25+ suppressor T cells, a loss of peripheral tolerance, and the development of organ-specific autoimmune disease in adult mice. Importantly, D3Tx does not lead to autoimmune disease in all mouse strains, indicating that this process is genetically controlled. Previously, we reported linkage of D3Tx-induced autoimmune ovarian dysgenesis (AOD) and its intermediate phenotypes, antiovarian autoantibody responsiveness, oophoritis, and atrophy, to five quantitative trait loci (QTL), designated Aod1 through Aod5. We also showed interaction between these QTL and H2 as well as Gasa2, a QTL controlling susceptibility to D3Tx-induced autoimmune gastritis. To physically map Aod1, interval-specific bidirectional recombinant congenic strains of mice were generated and studied for susceptibility to D3Tx-induced AOD. Congenic mapping studies revealed that Aod1 controls susceptibility to oophoritis and comprises two linked QTL with opposing allelic effects. Aod1a resides between D16Mit211 (23.3 cM) and D16Mit51 (66.75 cM) on chromosome 16. Aod1b maps proximal of Aod1a between D16Mit89 (20.9 cM) and D16Mit211 (23.3 cM) and includes the candidate genes stefin A1, A2, and A3 (Stfa1-Stfa3), inhibitors of cathepsin S, a cysteine protease required for autoantigen presentation, and the development of autoimmune disease of the salivary and lacrimal glands following D3Tx. cDNA sequencing revealed the existence of structural polymorphisms for both Stfa1 and Stfa2. Given the roles of cathepsins in Ag processing and presentation, Stfa1 and Stfa2 alleles have the potential to control susceptibility to autoimmune disease at the level of both CD4+CD25+ suppressor and CD4+CD25− effector T cells.