ラット血管痛モデルにおける循環器パラメーター変動のパワースペクトル解析

We investigated the dynamics of cardiovascular system in order to search for the characteristic of vascular pain model using power spectrum analysis. The animals were anesthetized with urethane (1.3g/kg, i.p.) and arterial cannula was inserted into a bifurcation of femoral artery. The recording of heartbeats was carried out by chest bipolar lead. Systolic blood pressure went through a transducer from femoral artery and measured it invasively. In the power spectrum density (PSD) of R-R intervals, it was almost the same as that of un-stimulating state at very low frequency (VLF, <0.08Hz) and low frequency (LF, 0.08-0.3Hz) and high frequency (HF, 0.3-4.0Hz). However, the arterial capsaicin (CAP, 0.2μg) evoked the increment of total PSD values, particularly at LF and VLF, were markedly different from those of pinching. Furthermore, the increase of PSD by CAP was inhibited by morphine (5mg/kg, s.c.). These results indicate that the useful possibility to observation of the autonomic nervous system dynamics induced by vascular pain as a characteristic of this model

冷水強制水泳誘発抗侵害作用の発現における脳内β-endorphinならびにεオピオイド受容体の関与

The involvement of endogenous opioid peptides and opioid receptors in supraspinal site on the antinociception induced by cold water swimming was determined using the mouse tail-flick test. The mice forced to swim in cold water for 3 min, showed the marked antinociception. The antinociception induced by cold water swimming was significantly attenuated by intracerebroventricularly (i.c.v.) pretreatment with antiserum against β-endorphin, but not against dynorphin A or [Leu^5] enkephalin. On the other hand, the antinociception was not affected by i.c.v. pretreatment with μ-opioid receptor antagonists β-funaltrexamine and D-Phe-cyclo-(Cys-Tyr-D-Trp-Orn-Thr-Pen)-Thr-NH_2, δ-opioid receptor antagonists naltrindole, 7-benzylidene naltrexone and naltriben, or κ-opioid receptor antagonist nor-binaltorphimine. The present results suggest that the antinociception induced by cold water swimming may be mainly mediated through the release of β-endorphin in the supraspinal site, which act on β-endorphin-sensitive non-μ-, non-δ-, and non-κ-opioid receptor, so called putative ε-opioid receptor

Enhancement of Host Resistance to Microbial Infections in Mice Fed a High Fat Diet by Lactobacillus casei Cells

The carbon clearance ability of female ddY mice was markedly reduced by feeding with a high fat-low carbohydrate (HFLC) diet for 8 weeks. The reduced clearance ability was restored by a single intraperiotoneal (ip) injection with heat-killed Lactobacillus casei (YIT 9018) cells (LC 9018). The ip injection of LC 9018 into the HFLC diet-fed mice led to a remarkable enhancement of nonspecific resistance when they were exposed to 50% lethal doses of Pseudomonas aeruginosa or herpes simplex virus, type 1. The resistance-enhancing capacity of LC 9018 against P. aeruginosa infection was significantly maintained for 7 days after the ip inoculation with LC 9018 in mice fed the HFLC diet. The reduced in vivo killing activity of peritoneal exudate cells (macrophage-rich) from mice fed the HFLC diet to P. aeruginosa infection was markedly augmented by the ip administration of LC 9018. The results indicate that LC 9018, one of the bacterial immunostimulants, may restore the reduced host defense functions in mice induced by feeding with a high fat diet for a long period