Genetic labeling of axo-axonic cells in the basolateral amygdala.

GABAergic neurons are classified into multiple subtypes based on morphology, physiological properties, and gene expression profiles. Although traditionally defined axo-axonic cells (AACs) are a unique type of interneuron that expresses parvalbumin and innervates the axon initial segment (AIS) of pyramidal neurons, a genetic marker for AACs in the basolateral amygdala (BLA) has not been identified. Here, we show that vasoactive intestinal peptide receptor 2 (Vipr2)-expressing interneurons exhibit anatomical and electrophysiological properties of AACs in the BLA. Using a reporter mouse expressing fluorescent proteins specifically in Vipr2+ cells, we analyzed the distribution, postsynaptic targeting and electrophysical properties of Vipr2+ cells in the BLA. More than half of the Vipr2+ cells showed parvalbumin immunoreactivity and innervated the AIS of pyramidal neurons in the BLA of Vipr2-tdTomato mice. Notably, most of the Vipr2+ cells showed fast-spiking properties. Furthermore, the use of a Cre-dependent adeno-associated virus led to more selective labeling of AACs in the BLA. These results suggest that AACs are genetically identifiable in the BLA without anatomical or physiological analysis.

Redetermination of the crystal structure of R 5Si4 (R = Pr, Nd) from single-crystal X-ray diffraction data.

The crystal structures of praseodymium silicide (5/4), Pr5Si4, and neodymium silicide (5/4), Nd5Si4, were redetermined using high-quality single-crystal X-ray diffraction data. The previous structure reports of Pr5Si4 were only based on powder X-ray diffraction data [Smith et al. (1967 ▸). Acta Cryst. 22 940-943; Yang et al. (2002b ▸). J. Alloys Compd. 339, 189-194; Yang et al., (2003 ▸). J. Alloys Compd. 263, 146-153]. On the other hand, the structure of Nd5Si4 has been determined from powder data [neutron; Cadogan et al., (2002 ▸). J. Phys. Condens. Matter, 14, 7191-7200] and X-ray [Smith et al. (1967 ▸). Acta Cryst. 22 940-943; Yang et al. (2002b ▸). J. Alloys Compd. 339, 189-194; Yang et al., (2003 ▸). J. Alloys Compd. 263, 146-153] and single-crystal data with isotropic atomic displacement parameters [Roger et al., (2006 ▸). J. Alloys Compd. 415, 73-84]. In addition, the anisotropic atomic displacement parameters for all atomic sites have been determined for the first time. These compounds are confirmed to have the tetra-gonal Zr5Si4-type structure (space group: P41212), as reported previously (Smith et al., 1967 ▸). The structure is built up by distorted body-centered cubes consisting of Pr(Nd) atoms, which are linked to each other by edge-sharing to form a three-dimensional framework. This framework delimits zigzag channels in which the silicon dimers are situated.

Nitric oxide-dependent hypotensive effects of wax gourd juice.

ETHNOPHARMACOLOGICAL RELEVANCE: The wax gourd (Benincasa hispida (Thunb) Cong.) is a long-season vegetable that has been used in traditional Chinese medicine to treat high blood pressure. However, precise details of its effect and the mechanism of action involved are still lacking. MATERIALS AND METHODS: Ten-fold-condensed wax gourd juice was used for the experiments. We measured (1) blood pressure of anesthetized normal Wistar rats in vivo, (2) isolated rat aortic contraction and relaxation, and (3) nitric oxide production from cultured porcine endothelial cells. The rats mentioned had not been treated with the investigational medicine. RESULTS: Intravenous injection of the juice produced a dose-dependent decrease in blood pressure. Treatment with the juice induced concentration-dependent relaxation of isolated rat aortic rings that had been precontracted with noradrenaline. The relaxation induced by the juice was strongly inhibited by treatment with the nitric oxide (NO) synthase inhibitor N(G)-nitro-l-arginine methyl ester hydrochloride (l-NAME) or endothelial denudation. Treatment with the juice produced NO from cultured porcine aortic endothelial cells. This NO production was significantly inhibited by l-NAME. CONCLUSIONS: The present findings suggest that wax gourd juice exerts a hypotensive effect via endothelium-dependent vasodilation. The main endothelium-derived relaxing factor involved might be NO.