Previous studies have focused considerable attention on the effects of estrogen on excitatory synaptic input to hippocampal CA1 pyramidal cells. Estrogen increases the density of dendritic spines and synapses on CA1 pyramidal cells and increases the sensitivity of these cells to excitatory synaptic input. Little is known, however, about the effects of estrogen on inhibitory synaptic input to CA1 pyramidal cells. We have used immunohistochemistry for glutamic acid decarboxylase and whole-cell voltage-clamp recording of IPSCs and EPSCs at multiple time points after estrogen treatment to (1) investigate estrogen regulation of synaptic inhibition in CA1 and (2) evaluate how estrogen affects the interaction between inhibitory and excitatory input to CA1 pyramidal cells. We find that estrogen transiently suppresses GABA A -mediated inhibition of CA1 pyramidal cells at a time point before changes in excitatory input to these cells occur. This finding is consistent with the suggestion that transient disinhibition of CA1 pyramidal cells is involved in estrogen-induced dendritic spine formation. We have also found that at a later time after estrogen, inhibition of CA1 pyramidal cells recovers in parallel with enhancement of NMDA-mediated excitatory input. The concurrent enhancement of GABA A and NMDA-mediated input to CA1 pyramidal cells restores a balance of excitatory and inhibitory input to these cells and increases the potential dynamic range of CA1 pyramidal cell responses to synaptic input.

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Dopamine in dialysate from the nucleus accumbens (NAcc) increases during sexual and feeding behavior and after administration of drugs of abuse, even those that do not directly activate dopaminergic systems (e.g., morphine or nicotine). These findings and others have led to hypotheses that propose that dopamine is rewarding, predicts that reinforcement will occur, or attributes incentive salience. Examining increases in dopamine in NAcc or striatum during sexual behavior in female rats provides a unique situation to study these relations. This is because, for the female rat, sexual behavior is associated with an increase in NAcc dopamine and conditioned place preference only under certain testing conditions. This experiment was conducted to determine what factors are important for the increase in dopamine in dialysate from NAcc and striatum during sexual behavior in female rats. The factors considered were the number of contacts by the male, the timing of contacts by the male, or the ability of the female to control contacts by the male. The results indicate that increased NAcc dopamine is dependent on the timing of copulatory stimuli, independent of whether the female rat is actively engaged in regulating this timing. For the striatum, the timing of copulatory behavior influences the magnitude of the increase in dopamine in dialysate, but other factors are also involved. We conclude that increased extracellular dopamine in the NAcc and striatum conveys qualitative or interpretive information about the rewarding value of stimuli. Sexual behavior in the female rat is proposed as a model to determine the role of dopamine in motivated behavior. Key words: dopamine; microdialysis; nucleus accumbens; striatum; motivation; sexual behavior; incentive salienceThe release of dopamine (DA) in the nucleus accumbens (NAcc) and, to a lesser extent, the striatum has been postulated to mediate the reinforcing properties of food, drugs of abuse, and the sexual experience (Wise and Rompre, 1989;Phillips et al., 1991;Robinson and Berridge, 1993). Alternatively, it has been suggested that an increase in extracellular DA in NAcc or striatum is associated with stimuli that predict reinforcement or that this activity attributes incentive salience to the stimuli (Phillips et al., 1993;Schultz et al., 1993;Berridge and Robinson, 1998). By looking at the time when DA increases in the striatum and the NAcc, we can gain additional insight into the roles of these neural structures in motivated behaviors.Sexual behavior in the female rat is unique among naturally occurring motivated behaviors in that copulation under standard laboratory conditions is not rewarding for the female rat (Oldenburger et al., 1992; Paredes and Alonso, 1997). In female rats and hamsters, there is enhanced DA in dialysate from striatum and NAcc during copulation (Meisel et al., 1993;Mermelstein and Becker, 1995;Pfaus et al., 1995). For female rats, however, this increase in NAcc DA has been found only under conditions in which the female can control or pace the tim...

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a debilitating syndrome of unknown etiology often postulated, but not proven, to be associated with microbial infection of the prostate gland. We hypothesized that infection of the prostate by clinically relevant uropathogenic Escherichia coli (UPEC) can initiate and establish chronic pain. We utilized an E. coli strain newly isolated from a patient with CP/CPPS (strain CP1) and examined its molecular pathogenesis in cell culture and in a murine model of bacterial prostatitis. We found that CP1 is an atypical isolate distinct from most UPEC in its phylotype and virulence factor profile. CP1 adhered to, invaded, and proliferated within prostate epithelia and colonized the prostate and bladder of NOD and C57BL/6J mice. Using behavioral measures of pelvic pain, we showed that CP1 induced and sustained chronic pelvic pain in NOD mice, an attribute not exhibited by a clinical cystitis strain. Furthermore, pain was observed to persist even after bacterial clearance from genitourinary tissues. CP1 induced pelvic pain behavior exclusively in NOD mice and not in C57BL/6J mice, despite comparable levels of colonization and inflammation. Microbial infections can thus serve as initiating agents for chronic pelvic pain through mechanisms that are dependent on both the virulence of the bacterial strain and the genetic background of the host.Prostatitis is a common urologic disease that results in over 2 million outpatient visits per year in the United States, including 8% of all visits to urologists and 1% of those to primary care physicians (5). The disease is classified into four categories, including acute bacterial prostatitis, chronic bacterial prostatitis, chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), and asymptomatic inflammatory prostatitis.The third disease category, CP/CPPS, accounts for approximately 90% of all chronic prostatitis cases and is clinically manifested as chronic pain in the perineum, rectum, prostate, penis, testicles, and abdomen (5). Despite the predominantly nonbacterial nature of CP/CPPS, up to 8% of patients with CP/CPPS harbor uropathogens that have traditionally been deemed to be of no significance (25). Numerous studies have also identified bacterial DNA in prostate samples from CP/ CPPS patients (9,19,20,22,25). CP/CPPS accompanied by uropathogens is differentiated from chronic bacterial prostatitis by the requirement for clinical symptoms of pelvic pain and the lack of recurrent urinary tract infections (UTIs).It has been suggested that the virulence of major uropathogens such as UPEC is dependent on the expression of multiple virulence factors (10, 15). Phylogenetic analysis suggests that prostatitis-causing uropathogenic Escherichia coli (UPEC) strains largely belong to the B2 phylogenetic group and exhibit a wide variety of virulence traits, including nonhemagglutinin adhesin-siderophore receptor (ihA), type 1 fimbriae (fimH), the salmochelin siderophore receptor (iroN), and outer membrane protease T (ompT) (1,12,...