Spontaneous recovery of fear differs among early – late adolescent and adult male mice

Adolescence is a vulnerable period for developing anxiety-related mental disorders such as post-traumatic stress disorder (PTSD), which requires a long-term course of therapy when a traumatic event has been experienced during childhood. However, the biological mechanism underlying these age-dependent characteristics remains unclear. In the present study, we used early adolescent, late adolescent and adult (4-, 8-, and 15-week old) male mice to examine age differences in fear memory, fear extinction, and spontaneous recovery of fear. We also measured the activation of extracellular signal-regulated kinase (ERK) 2 in the dorsal hippocampus (dHip) and the basolateral amygdala (BLA) following a spontaneous recovery test. Our major findings were as follows: (1) early adolescent and adult mice did not recover the fear response; only late adolescent mice recovered the fear response. (2) The ERK2 in the dHip was more activated after the spontaneous recovery test in late adolescent mice than in adult mice, and the ERK2 in the BLA was more activated after the spontaneous recovery test in adult mice than in late adolescent mice. These results suggest that there exists a unique period in which spontaneous recovery occurs and that these late adolescent behavioral signatures may be related to alteration in the ERK2 phosphorylation in the dHip and BLA.     

Inclusion body hepatitis due to adenovirus in pigeons

Inclusion body hepatitis (IBH) occurred on a pigeon farm of Japan. Basophilic and/or eosinophilic inclusion bodies were found in nuclei of many hepatocytes of all the four pigeons examined pathologically. The same inclusions were seen in epithelial cells of the uriniferous tubules and enterocytes of the small intestine. Ultrastructurally, the hepatic inclusions had viral particles morphologically identical to adenoviruses. The inoculum prepared from the affected liver produced neither cytopathic effects in chick embryo fibroblasts nor pock lesions on chorioallantoic membranes of developing chick embryos.     

Alpha1-adrenoceptor-mediated breakdown of phosphatidylinositol 4,5-bisphosphate inhibits pinacidil-activated ATP-sensitive K+ currents in rat ventricular myocytes

Phosphatidylinositol 4,5-bisphosphate (PIP2) stimulates ATP-sensitive K+ (K(ATP)) channel activity. Because phospholipase C (PLC) hydrolyzes membrane-bound PIP2, which in turn may potentially decrease K(ATP) channel activity, we investigated the effects of the alpha1-adrenoceptor-G(q)-PLC signal transduction axis on pinacidil-activated K(ATP) channel activity in adult rat and neonatal mouse ventricular myocytes. The alpha1-adrenoceptor agonist methoxamine (MTX) reversibly inhibited the pinacidil-activated K(ATP) current in a concentration-dependent manner (IC50 20.9+/-6.6 micromol/L). This inhibition did not occur when the specific alpha1-adrenoceptor antagonist, prazosin, was present. An involvement of G proteins is suggested by the ability of GDPbetaS to prevent this response. Blockade of PLC by U-73122 (2 micromol/L) or neomycin (2 mmol/L) attenuated the MTX-induced inhibition of K(ATP) channel activity. In contrast, the MTX response was unaffected by protein kinase C inhibition or stimulation by H-7 (100 micro mol/L) or phorbol 12,13-didecanoate. The MTX-induced inhibition became irreversible in the presence of wortmannin (20 micro mol/L), an inhibitor of phosphatidylinositol-4 kinase, which is expected to prevent membrane PIP2 replenishment. In excised inside-out patch membranes, pinacidil induced a significantly rightward shift of ATP sensitivity of the channel. This phenomenon was reversed by pretreatment of myocytes with MTX. Direct visualization of PIP2 subcellular distribution using a PLCdelta pleckstrin homology domain-green fluorescent protein fusion constructs revealed reversible translocation of green fluorescent protein fluorescence from the membrane to the cytosol after alpha1-adrenoceptor stimulation. Our data demonstrate that alpha1-adrenoceptor stimulation reduces the membrane PIP2 level, which in turn inhibits pinacidil-activated K(ATP) channels.     

Aplastic Anemia in a Patient with Cronkhite-Canada Syndrome

Cronkhite-Canada syndrome (CCS) is a rare polyposis disorder accompanied by alopecia and onychodystrophy. A 63-year-old man with a history of CCS and repeated embolism developed progressive thrombocytopenia and mild anemia. Laboratory testing, a bone marrow examination, and magnetic resonance imaging of the spine resulted in a diagnosis of concurrent aplastic anemia (AA). Paroxysmal nocturnal hemoglobinuria (PNH)-type cells were detected in a peripheral blood specimen. In addition, human leukocyte antigen (HLA) included DRB1*15:01 and DRB1*15:02. Mesalazine was discontinued in consideration of possible drug-induced pancytopenia. Immunosuppressive therapy ameliorated both the gastrointestinal symptoms of CCS and pancytopenia. A common autoimmune abnormality might underlie both CCS and AA.     

The relationship between positive and negative automatic thought and activity in the prefrontal and temporal cortices: A multi-channel near-infrared spectroscopy (NIRS) study

Background

Recently, neurobiological studies of the cognitive model of depression have become vastly more important, and a growing number of such studies are being reported. However, the relationship between the proportion of positive and negative automatic thought and activity in the prefrontal and temporal cortices has not yet been explored. We examined the relationship between brain activity and the proportion of positive and negative automatic thought in patients with major depressive disorder (MDD), using multi-channel near-infrared spectroscopy (NIRS).

Methods

We recruited 75 individuals with MDD (36 females; mean age=39.23±12.49). They completed the Hamilton Rating Scale for Depression, Automatic Thoughts Questionnaire-Revised, Japanese version of the National Adult Reading Test, and the State-Trait Anxiety Inventory. Brain activation was measured by 52-channel NIRS.

Results

We found that activation in the vicinity of the right superior temporal gyrus is related to a deviation to negative of the proportion of positive and negative thoughts in individuals with MDD. Left dorsolateral prefrontal cortex activity was higher in the group with comparatively frequent positive thought.

Limitations

Our participants were patients taking antidepressant medication, which is known to influence brain activity. Second, the poor spatial resolution of NIRS increases the difficulty of identifying the measurement position.

Conclusions

We found that activation of the prefrontal and temporal cortices is related to the proportion of automatic thoughts in the cognitive model of depression.