Appearance of prolactin-releasing peptide-producing neurons in the area postrema of adrenalectomized rats

Prolactin-releasing peptide (PrRP) was found to be a novel hypothalamic peptide that stimulates prolactin release in vitro and in vivo. In the normal adult rat brain, PrRP neurons are known to be located in only three areas, i.e. the dorsomedial hypothalamic nucleus, ventrolateral reticular formation; and nucleus of the tractus solitarius in the medulla oblongata. These PrRP neurons project neurites into various brain areas, including regions such as the paraventricular nucleus, supraoptic nucleus, and bed nucleus of the stria terminalis. Both PrRP nerve fibers and a high level of PrRP receptor, UHR-1, mRNA are observed in the area postrema (AP),but no PrRP neurons are detected in the AP of normal rats. In this study, we clearly demonstrated that PrRP-producing cells newly appeared in the AP of adrenalectomized rats by in situ hybridization and immunocytochemistry. Our results suggest that PrRP may have some important roles in the AP of adrenalectomized rats. This is the first report demonstrating the appearance of PrRP-positive cells in the AP.     

Chronic morphine treatment increases the expression of the neural cell adhesion molecule in the dorsal horn of the mouse spinal cord

It is well known that prolonged exposure to morphine results in tolerance to morphine-induced antinociception. In the present study, we found that mice that were tolerant to morphine-induced antinociception exhibited an increase in immunoreactivity for the neural cell adhesion molecule in the dorsal horn of the spinal cord, which was highly overlapped with immunoreactivity for the increased metabotropic glutamate receptor 5 induced by morphine. These findings support the idea that repeated stimulation of μ-opioid receptors increases the expression of neural cell adhesion molecule and metabotropic glutamate receptor 5. This phenomenon leads to the enhanced excitatory synaptic transmission in the dorsal horn of the spinal cord, and in turn suppresses the morphine-induced antinociception.     

Vinyl polymerization. 120. Mutual copolymerization of p-substituted styrenes through radical mechanism

The radical mutual copolymerization of p-substituted styrenes, such as p-methoxy-, p-chloro-, p-bromo-, p-cyanostyrene, and styrene was carried out with one another at 30°C. in the dark. As initiator, azobisisobutyronitrile was used. The plots of the copolymerization rates against HAMMETT 's σ values showed no linear relationships and the concave curves were obtained therefrom. The relative reactivities of p-substituted styrenes with a definite p-substituted polystyryl radical, which were shown by the reciprocal of monomer reactivity ratio r₁, were plotted against σ values and concave curves were also obtained. The relative reactivities of p-substituted polystyryl radicals with p-substituted styrene were calculated from the ratios r₂ and the propagation rate constants in homopolymerization. the plots of them against σ values gave straight lines with different ρ values, according to the polarity of substituents. These results suggest that polar structures in transition state affected markedly the copolymerization rates. The effect of substituents on resonance stabilization was also quantitatively estimated.     

Essential role of rho kinase in the ca2+ Sensitization of Prostaglandin F2α-Induced Contraction of Rabbit Aortae

Although the prostate gland is a rich source of α1-adreno- (α1-AR) and m1-cholino receptors (m1-AChR), the membrane processes associated with their activation in glandular epithelial cells is poorly understood. We used the whole-cell patch-clamp technique to show that the agonists of the respective receptors, phenylephrine (PHE) and carbachol (CCh), activate cationic membrane currents in lymph node carcinoma of the prostate (LNCaP) human prostate cancer epithelial cells, which are not dependent on the filling status of intracellular IP₃-sensitive Ca²⁺ stores, but directly gated by diacylglycerol (DAG), as evidenced by the ability of its membrane permeable analogue, OAG, to mimic the effects of the agonists. The underlying cationic channels are characterized by the weak field-strength Eisenman IV permeability sequence for monovalent cations ( P _K(25) > P _Cs(4.6) > P _Li(1.4) > P _Na(1.0)), and the following permeability sequence for divalent cations: P _Ca(1.0) > P _Mg(0.74) > P _Ba(0.6) > P _Sr(0.36) > P _Mn(0.3). They are 4.3 times more permeable to Ca²⁺ than Na⁺ and more sensitive to the inhibitor 2-APB than SK&F 96365. RT-PCR analysis shows that DAG-gated members of the transient receptor potential (TRP) channel family, including TRPC1 and TRPC3, are present in LNCaP cells. We conclude that, in prostate cancer epithelial cells, α1-ARs and m1-AChRs are functionally coupled to Ca²⁺-permeable DAG-gated cationic channels, for which TRPC1 and TRPC3 are the most likely candidates.     

Vinyl polymerization. 294. Decomposition of tetramethyltetrazene in the presence of p-substituted benzyl chlorides

A study was made of the polymerization of acrylonitrile in dimethylformamide (DMF) initiated by the binary systems of tetramethyltetrazene (TMT) and p-substituted benzyl chlorides. The polymerization rate increased linearly with the σ-constants of substituents as electron-releasing groups were introduced to the phenyl ring of benzyl chloride. In order to elucidate the initiation mechanism of the polymerization, a kinetic investigation was also undertaken of the decomposition of TMT in the presence of p-substituted benzyl chlorides in DMF. The decomposition rate was first-order in TMT and first-order in p-substituents benzyl chloride. The decomposition rate also increased with the σ constants of substituents as electron-releasing groups were introduced. On the basis of the results, the initiation mechanism for the polymerization was discussed.     

Late-onset obesity in mice transgenic for the human renin gene

We previously generated a strain of transgenic mice carrying the human renin gene, hRN8-12, in the background of C57BL/6j. In this study, we discovered that hRN8-12 male mice, but not females, developed obesity starting at 15 weeks of age. The body weight of 60-week-old male transgenic mice was 2 times higher than that of age-matched wild-type mice. Interestingly, male mice heterozygous for the human renin gene showed moderate weight gain compared with transgenic and wild-type mice. Obese hRN8-12 mice exhibited hyperglycemia, hyperinsulinemia, hyperleptinemia, and hyperlipidemia, and increase in weight in the adipose tissue, liver, heart, and kidneys. Histological analysis demonstrated that fatty hRN8-12 mice developed hypertrophy of pancreatic islets and fatty liver. These results suggested that hRN8-12 mice are associated with obesity dependent on the transgene dosage and should be a genetic model for late-onset obesity.     

Studies on epidermal growth factor receptor signaling in vertebrate limb patterning.

The epidermal growth factor receptor (EGFR) regulates multiple patterning events in Drosophila limb development, but its role in vertebrate limb morphogenesis has received little attention. The EGFR and several of its ligands are expressed in developing vertebrate limbs in manners consistent with potential patterning roles. To gain insight into functions of EGFR signaling in vertebrate limb development, we expressed a constitutively active EGFR in developing chick limbs in ovo. Expression of activated EGFR causes pre- and postaxial polydactyly, including mirror-image-type digit duplication, likely due to induction of ectopic expression and/or modulation of genes involved in anterior-posterior (AP) patterning such as Sonic hedgehog (Shh), dHand, Patched (Ptc), Gli3, Hoxd13, Hoxd11, bone morphogenetic protein 2 (Bmp2), Gremlin, and FGF4. Activation of EGFR signaling dorsalizes the limb and alters expression of the dorsal-ventral (DV) patterning genes Wnt7a, Lmx, and En1. Ectopic and/or extended FGF8 expressing apical ectodermal ridges (AERs) are also seen. Interdigital regression is inhibited and the digits fail to separate, leading to syndactyly, likely due to antiapoptotic and pro-proliferative effects of activated EGFR signaling on limb mesoderm, and/or attenuation of interdigital Bmp4 expression. These findings suggest potential roles for EGFR signaling in AP and DV patterning, AER formation, and cell survival during limb morphogenesis.     

Flavonoids such as luteolin, fisetin and apigenin are inhibitors of interleukin-4 and interleukin-13 production by activated human basophils

BACKGROUND: We have previously shown that fisetin, a flavonol, inhibits IL-4 and IL-13 synthesis by allergen- or anti-IgE-antibody-stimulated basophils. This time, we investigated the inhibition of IL-4 and IL-13 production by basophils by other flavonoids and attempted to determine the fundamental structure of flavonoids related to inhibition. We additionally investigated whether flavonoids suppress leukotriene C4 synthesis by basophils and IL-4 synthesis by T cells in response to anti-CD3 antibody. METHODS: Highly purified peripheral basophils were stimulated for 12 h with anti-IgE antibody alone or anti-IgE antibody plus IL-3 in the presence of various concentrations of 18 different kinds of flavones and flavonols. IL-4 and IL-13 concentrations in the supernatants were then measured. Leukotriene C4 synthesis was also measured after basophils were stimulated for 1 h in the presence of flavonoids. Regarding the inhibitory activity of flavonoids on IL-4 synthesis by T cells, peripheral blood mononuclear cells were cultured with flavonoids in anti-CD3-antibody-bound plates for 2 days. RESULTS: Luteolin, fisetin and apigenin were found to be the strongest inhibitors of both IL-4 and IL-13 production by basophils but did not affect leukotriene C4 synthesis. At higher concentrations, these flavonoids suppressed IL-4 production by T cells. Based on a hierarchy of inhibitory activity, the basic structure for IL-4 inhibition by basophils was determined. CONCLUSIONS: Due to the inhibitory activity of flavonoids on IL-4 and IL-13 synthesis, it can be expected that the intake of flavonoids, depending on the quantity and quality, may ameliorate allergic symptoms or prevent the onset of allergic diseases.