Women with Premenstrual Dysphoria Lack the Seemingly Normal Premenstrual Right-Sided Relative Dominance of 5-HTP-Derived Serotonergic Activity in the Dorsolateral Prefrontal Cortices - A Possible Cause of Disabling Mood Symptoms.

STUDY OBJECTIVE: To investigate potential quantitative and qualitative differences in brain serotonergic activity between women with Premenstrual Dysphoria (PMD) and asymptomatic controls. BACKGROUND: Serotonin-augmenting drugs alleviate premenstrual mood symptoms in the majority of women with PMD while serotonin-depleting diets worsen PMD symptoms, both indicating intrinsic differences in brain serotonergic activity in women with PMD compared to asymptomatic women. METHODS: Positron-emission tomography with the immediate precursor of serotonin, 5-hydroxytryptophan (5-HTP), radiolabelled by 11C in the beta-3 position, was performed in the follicular and luteal phases for 12 women with PMD and 8 control women. Brain radioactivity-a proxy for serotonin precursor uptake and synthesis-was measured in 9 regions of interest (ROIs): the right and left sides of the medial prefrontal cortex, dorsolateral prefrontal cortex, putamen and caudate nucleus, and the single "whole brain". RESULTS: There were no significant quantitative differences in brain 5-HTP-derived activity between the groups in either of the menstrual phases for any of the 9 ROIs. However, multivariate analysis revealed a significant quantitative and qualitative difference between the groups. Asymptomatic control women showed a premenstrual right sided relative increase in dorsolateral prefrontal cortex 5-HTP derived activity, whereas PMD women displayed the opposite (p = 0.0001). Menstrual phase changes in this asymmetry (premenstrual-follicular) correlated with changes in self ratings of 'irritability' for the entire group (rs = -0.595, p = 0.006). The PMD group showed a strong inverse correlation between phase changes (premenstrual-follicular) in plasma levels of estradiol and phase changes in the laterality (dx/sin) of radiotracer activity in the dorsolateral prefrontal ROI (rs = -0.635; 0.027). The control group showed no such correlation. CONCLUSION: Absence of increased premenstrual right-sided relative 5-HTP-derived activity of the dorsolateral prefrontal cortices was found to strongly correlate to premenstrual irritability. A causal relationship here seems plausible, and the findings give further support to an underlying frontal brain disturbance in hormonally influenced serotonergic activity in women with PMD. Because of the small number of subjects in the study, these results should be considered preliminary, requiring verification in larger studies.

Prolactin regulation of the expression of TNF-alpha, IFN-gamma and IL-10 by splenocytes in murine multiple low dose streptozotocin diabetes.

Previously, the hormone prolactin (PRL) has been found to protect against development of type 1 diabetes induced by multiple injections of streptozotocin (STZ) in mice. To further investigate this effect of PRL, C57BL/Ks mice were injected intraperitoneally with STZ (40 mg/kg body weight) or NaCl for 5 days and PRL (4 mg/kg body weight) or NaCl for 14 days. On day 15, splenocytes were isolated from the in vivo treated mice. Spleen cell preparations depleted in erythrocytes and macrophages were stained for cytoplasmic TNF-alpha, IFN-gamma and IL-10 and analyzed with flow cytometry. Isolated spleen cells were also cultured (RPMI 1640+10% fetal bovine serum) for 24 h. Thereafter, cytokine mRNA expression by the spleen cells was measured by real-time PCR and cytokine secretion determined by enzyme linked immunosorbent assay (ELISA). Freshly isolated spleen cell preparations from PRL and STZ+PRL treated animals seemed to have an increased frequency of IL-10 positive cells compared to controls. In cultured spleen cells isolated from STZ treated mice, IFN-gamma and IL-10 mRNA expression was up-regulated. PRL treatment down-regulated the mRNA expression of these cytokines and also TNF-alpha in the splenocytes obtained from animals treated with STZ. The accumulation of these cytokines in the cultures of the explanted splenocytes showed only minor differences between the experimental groups. Overall, the data seems to favor the view that PRL enhanced a Th2 response, which may reflect the preventive effect of PRL against development of multiple low dose STZ diabetes in mice.

Cytokine release by murine spleen cells following multiple low dose streptozotocin-induced diabetes and treatment with a TNFalpha transcriptional inhibitor.

We recently reported that administration of 9-[(1R, 3R)-trans-cyclopentan-3-ol] adenine (MDL 201,449A), a transcriptional inhibitor of TNFalpha, decreased hyperglycemia in murine diabetes induced by multiple low doses of streptozotocin (MLDSTZ). In the present study, we first investigated if in vivo administration of MDL 201,449A in the MLDSTZ model affects cytokine release from cultured spleen cells. Secondly, we studied how MDL 201,449A affects cytokine release from normal cultured spleen cells. In all experiments, the mitogen concanavalin A (2 micro g/ml) was added to the cultured spleen cells in order to enhance cytokine release. MLDSTZ treatment in vivo caused increased IFNgamma secretion, a decreased/retarded rate of increased TNFalpha accumulation, whereas IL-10 production was not altered compared to vehicle-treated mice. MDL 201,449A treatment of MLDSTZ mice did not affect cytokine release from spleen cells subsequently cultured in the absence of MDL 201,449A. We also studied cytokine release from normal spleen cells in the presence or absence of MDL 201,449A. Production of TNFalpha, IFNgamma and IL-10 was all suppressed by the drug. In groups where exposure to MDL 201,449A was discontinued, cytokine levels increased promptly and in the case of TNFalpha secretion, it exceeded the production from control cells. Our data suggest an enhanced Th1 cytokine secretion from spleen cells derived from MLDSTZ-treated mice. MDL 210,449A may be a potent inhibitor of cytokine secretion, albeit not completely selective for TNFalpha. However, when MDL 201,449A is withdrawn, there may be a rebound phenomenon of increased TNFalpha secretion.

Inducible nitric oxide synthase is involved in acid-induced gastric hyperemia in rats and mice.

The role of different isoforms of nitric oxide synthase (NOS) in the gastric mucosal hyperemia, induced by 155 mM luminal hydrochloric acid (pH approximately 0.8) without a barrier breaker, was investigated. Rats were anesthetized with Inactin (120 mg/kg ip), and mice were anesthetized with Forene (2.2% in 40% oxygen gas at 150 ml/min); the gastric mucosa was exteriorized. Gastric mucosal blood flow was measured with laser-Doppler flowmetry (LDF) in rats treated with Nomega-nitro-l-arginine (l-NNA; unspecific NOS inhibitor), l-N6-(1-iminoethyl)lysine [l-NIL; inducible (i) NOS inhibitor], or S-methyl-l-thiocitrulline [SMTC; neuronal (n) NOS inhibitor], 10 mg/kg, followed by 3 mg. kg-1. h-1 iv, in iNOS-deficient (-/-) and nNOS(-/-) mice. mRNA was isolated from the gastric mucosa in iNOS(-/-) and wild-type (wt) mice, and real-time RT-PCR was performed. The effect of 155 mM acid on gastric mucosal permeability was determined by measuring the clearance of 51Cr-EDTA from blood to lumen. LDF increased by 48 +/- 13% during 155 mM HCl luminally, an increase that was abolished by l-NNA, SMTC, or l-NIL. In iNOS wt mice, LDF increased by 33 +/- 8% during luminal acid. The blood flow increase was attenuated substantially in iNOS(-/-) mice. RT-PCR revealed iNOS mRNA expression in the gastric mucosa in the iNOS wt groups. The blood flow increase in response to acid was not abolished in nNOS(-/-) mice (nNOS-sufficient mice, 39 +/- 18%; heterozygous mice, 25 +/- 19%; -/- mice, 19 +/- 7%). Mucosal permeability was transiently increased during 155 mM HCl. The results suggest that iNOS is constitutively expressed in the gastric mucosa and is involved in acid-induced hyperemia, suggesting a novel role for iNOS in gastric mucosal protection.