Simultaneous activation of the α1A-, α1B- and α1D-adrenoceptor subtypes in the nucleus accumbens reduces accumbal dopamine efflux in freely moving rats.

Intra-accumbal infusion of the α1-adrenergic agonist methoxamine, which has comparable affinity for α1A-, α1B- and α1D-adrenoceptor subtypes, fails to alter noradrenaline efflux but reduces dopamine efflux in the nucleus accumbens of rats. In-vivo microdialysis experiments were carried out to analyse the putative contribution of α1A-, α1B- and α1D-adrenoceptor subtypes to the methoxamine-induced decrease in accumbal dopamine efflux in freely moving rats. The drugs used were dissolved in the infusion medium and administered locally through a dialysis membrane. Intra-accumbal infusions of the α1A-adrenoceptor antagonist 5-methylurapidil (6 pmol), the α1B-adrenoceptor antagonist cyclazosin (0.6 and 6 pmol) and the α1D-adrenoceptor antagonist BMY 7378 (0.6 pmol) did not alter accumbal efflux of noradrenaline or dopamine: pretreatment with each of these α1-adrenoceptor subtype-selective antagonists counteracted the methoxamine (24 pmol)-induced decrease in accumbal dopamine efflux. Doses indicated are the total amount of drug administered over a 60-min infusion period. These results clearly suggest that the α1A-, α1B- and α1D-adrenoceptor subtypes in the nucleus accumbens mediate the α1-adrenergic agonist methoxamine-induced decrease in accumbal dopamine efflux. The present study also provides in-vivo neurochemical evidence indicating that concomitant, but not separate, activation of the α1A-, α1B- and α1D-adrenoceptors in the nucleus accumbens is required for α1-adrenergic inhibition of accumbal dopaminergic activity.

Mitral endocarditis in hypertrophic obstructive cardiomyopathy with leaflet perforation.

We present a case of mitral endocarditis in hypertrophic obstructive cardiomyopathy with systolic anterior motion of anterior leaflet. Perforated anterior leaflet was repaired and extended septal myectomy was concomitantly performed to control systolic anterior motion and mitral regurgitation.

Intragingival injection of Porphyromonas gingivalis-derived lipopolysaccharide induces a transient increase in gingival tumour necrosis factor-α, but not interleukin-6, in anaesthetised rats.

This study used in vivo microdialysis to examine the effects of intragingival application of lipopolysaccharide (LPS) derived from Porphyromonas gingivalis (Pg-LPS) on gingival tumour necrosis factor (TNF)-α and interleukin (IL)-6 levels in rats. A microdialysis probe with an injection needle attached to the surface of the dialysis membrane was implanted into the gingiva of the upper incisor. For comparison, the effects of LPS derived from Escherichia coli (Ec-LPS) on IL-6 and TNF-α levels were also analysed. Pg-LPS (1 µg/1 µL) or Ec-LPS (1 or 6 µg/1 µL) was applied by microsyringe, with gingival dialysates collected every hour. Enzyme-linked immunosorbent assay (ELISA) revealed that gingival dialysates contained approximately 389 pg·mL⁻¹ of IL-6 basally; basal TNF-α levels were lower than the detection limit of the ELISA. Pg-LPS failed to alter IL-6 levels but markedly increased TNF-α levels, which remained elevated for 2 h after treatment. Neither IL-6 nor TNF-α were affected by Ec-LPS. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed that the gingiva expresses Toll-like receptor (TLR) 2 and TLR4 mRNA. Immunohistochemical examination showed that TLR2 and TLR4 are expressed by gingival epithelial cells. The present study provides in vivo evidence that locally applied Pg-LPS, but not Ec-LPS, into the gingiva transiently increases gingival TNF-α without affecting IL-6. The present results suggest that TLR2 but not TLR4 expressed on gingival epithelial cells may mediate the Pg-LPS-induced increase in gingival TNF-α in rats.

Synergistic, but not separate, stimulation of accumbal ß1- and ß2-adrenoceptors alters the accumbal dopamine efflux in freely moving rats.

The effects of intra-accumbal infusion of selective agonists for the ß-adrenoceptor subtypes on the noradrenaline and dopamine efflux in the nucleus accumbens of freely moving rats were investigated, using in vivo microdialysis. Neither ß1-(dobutamine: 0.06 and 0.12 pmol) nor ß2-adrenoceptor agonist (salbutamol: 0.36 and 3.6 pmol) altered the basal noradrenaline and dopamine efflux in the nucleus accumbens. Co-administration of 0.06 pmol of dobutamine with salbutamol (3.6 pmol) did not affect the noradrenaline levels, but it increased the dopamine efflux to approximately 120%. Co-administration of 0.12 pmol of dobutamine with salbutamol (0.36 or 3.6pmol) also increased DA efflux to approximately 120% without affecting noradrenaline levels. The non-selective ß-adrenoceptor antagonist l-propranolol (1200 pmol) that did not alter the basal noradrenaline and dopamine levels, suppressed the dopamine efflux, induced by co-administration of dobutamine (0.12 pmol) and salbutamol (3.6 pmol). The doses mentioned are the total amount of drug over the 60-min infusion period. The present results support our previously reported conclusion that stimulation of accumbal ß-adrenoceptors which are suggested to be postsynaptically located on accumbal dopaminergic terminals, can enhance the dopamine efflux in the nucleus accumbens. The present study also provides in vivo neurochemical evidence that concomitant, but not separate, activation of accumbal ß1- and ß2-adrenoceptors synergistically increases the accumbal dopamine efflux.

Osteoblasts stimulate osteoclastogenesis via RANKL expression more strongly than periodontal ligament cells do in response to PGE(2).

OBJECTIVE: Periodontal ligament cells (PDLs) produce prostaglandin E(2) (PGE(2)) in response to orthodontic force. PGE(2) is a potent osteoclast-inducing factor that induces the receptor activator of nuclear factor-κB ligand (RANKL). Some studies reported that PDLs express RANKL in response to mechanical stress, whereas another study reported that they do not. Based on an immunohistochemical study, RANKL expression is localized around the alveolar bone surface 3 days after tooth movement. However, ankylosed teeth cannot be moved by therapeutic mechanical stress, suggesting that PDLs play a major role in alveolar bone resorption. In this study, we compared the functional difference in osteoclastogenesis between human PDLs (HPDLs) and normal human osteoblasts (HOBs) as a direct effect of PGE(2) exposure. DESIGN: We examined the expression of RANKL, osteoprotegerin, and macrophage colony-stimulating factor after 48-h culture with or without PGE(2) (10(-11) to 10(-5)M) in HPDLs and HOBs. Then to confirm whether RANKL produced by PGE(2) treatment induces osteoclastogenesis or not, RAW264.7 cells were co-cultured on HPDLs or HOBs pretreated with 10(-6)M of PGE(2). RESULT: PGE(2) exposure increased significantly RANKL expression in HOBs compared with HPDLs. PGE(2) exposure significantly decreased osteoprotegerin expression in HPDLs compared with HOBs. The number of tartrate-resistant acid phosphatase staining osteoclast-like cells from RAW264.7 cells increased significantly by PGE(2) pretreatment in HOBs and was reduced by small interfering RNA knockdown of RANKL. CONCLUSION: These results suggest that osteoblasts strongly influence the stimulation of osteoclastogenesis via RANKL, induced by PGE(2) in periodontal tissues, compared with PDLs.

Synergistic effect of green tea catechins on cell growth and apoptosis induction in gastric carcinoma cells.

(-)-Epigallocatechin gallate (EGCG), a major component of green tea catechins, is known to inhibit cell growth and to induce apoptosis in a variety of cultured cells. We examined effects of green tea catechins in cultured cells derived from human gastric carcinoma. The proliferation of four cell lines (MKN-1, MKN-45, MKN-74 and KATO-III) was inhibited with EGCG in a dose-dependent manner. The growth of MKN-45 cells was most efficiently inhibited by the treatment (IC(50): 40 muM EGCG) among the four cell lines, while KATO-III cells were most insensitive (IC(50): 80-150 muM) to the EGCG treatment. In addition, (-)-epicatechin (EC) had a major synergistic effect on the induction of apoptosis in MKN-45 cells treated with EGCG; however it had little effect on the inhibition of cell growth induced by EGCG. To study the molecular mechanisms behind the induction of apoptosis by EGCG, the activity of caspases in MKN-45 cells treated with EGCG was examined. Activity levels of caspases-3, -8 and -9 were elevated in EGCG-treated cells, suggesting that these caspases are involved in the apoptosis induced by EGCG. Furthermore, the synergistic effect of EC with EGCG on the induction of apoptosis was specifically canceled by catalase treatment, suggesting that the synergism involves the extracellular production of reactive oxygen species.