Yoichi Takeyama

Orexin-1 receptor immunoreactivity in chemically identified target neurons in the rat hypothalamus.

Immunohistochemistry and Western blotting were used to determine the distribution of orexin receptors in the rat brain. Strong orexin receptor 1 (OX1R) immunoreactivity was detected in the hypothalamus including the arcuate, ventromedial, and tuberomammillary nuclei that are involved in feeding regulation. The neuropeptide Y- and proopiomelanocortin-containing neurons of the arcuate nucleus, which act to stimulate or to inhibit feeding, respectively, displayed intense OX1R immunoreactivity by double immunostaining. Western blotting analysis yielded a 50-kDa major band of OX1R.

Effects of corticotropin-releasing factor on intermediolateral cell column neurons of newborn rats

Corticotropin-releasing factor (CRF) is a neuropeptide that mediates neuroendocrine, autonomic, and behavioral processes associated with the stress response. CRF-containing fibers and receptors are found in various regions of the central nervous system including the spinal cord. Here, we report excitatory effects of CRF on sympathetic preganglionic neurons in the intermediolateral cell column (IML) of in vitro spinal cord preparations from newborn rats. We also examine the receptor subtypes that are involved in the CRF effects. Application of CRF significantly depolarized the IML neurons and increased the frequency of excitatory postsynaptic potentials (EPSPs) in the IML neurons. These effects were blocked by the CRF receptor 1 antagonist, antalarmin. Menthol, a transient receptor potential channel M8 agonist, depressed EPSPs enhanced by CRF. Our findings suggested that CRF depolarized the IML neurons via direct postsynaptic action and CRF-affected interneurons located in the spinal cord send EPSPs to IML neurons. These excitatory effects of CRF may be caused through CRF1 receptors but not CRF2 receptors.

284 EFFECTS OF CORTICOTROPIN-RELEASING FACTOR ON INTERMEDIOLATERAL CELL COLUMN NEURONS

Background: CRF receptors are widely distributed in the central nervous system including the spinal cord. Although CRF indirectly participates in control of the blood pressure, it is unknown whether CRF is involved in blood pressure control via direct action on central neurons. Here, we report effects of CRF on sympathetic preganglionic neurons in the intermediolateral cell column (IML) of the spinal cord. Methods: Transverse slices of Th2 segment from newborn rats (0-4 days old) were superfused by artificial cerebrospinal fluid. Membrane potentials of IML neurons were recorded by whole-cell patch-clamp. Preganglionic neurons were confirmed by antidromic action potential induced by Th2 ventral root stimulation and cell staining by Lucifer Yellow. CRF (50 nM) was bath-applied. We measured the membrane potential change and counted the number of excitatory postsynaptic potentials (EPSPs) of the IML neurons. Results: The frequency of EPSPs in the IML neurons was 3.67 ± 3.57 Hz (n = 9) in control solution. Application of CRF increased the number of EPSPs (220%) and induced membrane depolarization by 2.4 ± 1.3 mV. The increase of EPSPs number by CRF was attenuated by pretreatment of a CRF-1 antagonist, antalarmin (124%) but not by pretreatment of a CRF-2 antagonist, astressin2B (268). Conclusion: Our findings suggest that CRF affected directly IML neurons and interneurons in the spinal cord. Moreover, CRF exerted the excitatory effect on the IML neurons through CRF-1 receptors, whereas effect via CRF-2 might be rather inhibitory. Thus, CRF-related drugs are expected as one of the choices of the pharmacologic control of the blood pressure.

1158-53 Suppressive Effects of Eplerenone on Accumulation of Extra Cellular Matrix in Neointima After Coronary Stent Implantation Using Swine

matched between non-dilated and dilated vessels. Differential expression of 12 proteinswas observed between the groups and direct sequencing of digested peptides demon-strated that these proteins regulate the structural integrity of the vessel wall. Rapamycinblocked the expression of specific proteins, including lamin A, vimentin, alpha-1-antit-rypsin, and alpha-actin. In addition, rapamycin significantly reduced the deposition ofelastin, collagen III and fibronectin within the vascular wall. Neointimal formation was like-wise decreased and this (0.71±0.1 vs 1.4±0.12 intima-media-ratio, rapamycin vs. vehicle,respectively) could be attributed to the inhibitory properties of rapamycin on ECM deposi-tion and smooth muscle cell proliferation.Proteomic profiling of restenotic lesions unveils differential expression of structural pro-teins that regulate vessel wall integrity. Intramural infusion of rapamycin directly to theinjured site differentially blocked the expression of these proteins as well as smooth mus-cle cell proliferation and the deposition of ECM, providing a rationale for the use of rapa-mycin to prevent unfavorable remodeling of the vascular wall that occurs followingangioplasty.