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Opioid peptides were analysed in tissue extracts of various brain structures and the pituitary gland from rats sacrificed by microwave irradiation, and compared with peptide levels in tissue extracts from decapitated rats. Dynorphin A, dynorphin B and Leu-enkephalinArg6, derived from prodynorphin, and Met-enkephalinArg6Phe7 from proenkephalin, were(More)
Dynorphin A, a prodynorphin-derived peptide, is able to induce neurological dysfunction and neuronal death. To study dynorphin cytotoxicity in vitro, prodynorphin-derived peptides were added into the culture medium of nonneuronal and neuronal cells or delivered into these cells by lipofection or electroporation. Cells were unaffected by extracellular(More)
Olfactory bulbectomy (OBX) induces behavioral, physiological, and neurochemical alterations resembling clinical depression and is widely used as an animal model of depression. It has been reported that depression is a critical cause of child abuse and neglect and that maternal behavior involves dopaminergic neurons of the mesolimbic pathway. In a previous(More)
To understand better which voltage-dependent calcium channels (VGCCs) are involved in nociceptive neurotransmission, we investigated the pharmacological properties and distribution of VGCCs in the mouse spinal cord. A behavioral assay revealed that intrathecal injections of omega-agatoxin TK, omega-agatoxin IVA, omega-conotoxin GVIA, and SNX-482, which(More)
We investigated the relationship between the antinociceptive effect of the opiate agonist loperamide at the spinal level and its inhibitory effect on calcium influx. Intrathecal administration of loperamide showed a significant antinociceptive effect in the formalin test, which was not prevented by naloxone. On the other hand, no significant effects were(More)
We investigated the antinociceptic effects of cilnidipine, a dihydropyridine derivative which acts on both L- and N-type voltage-dependent calcium channels, in mice. Intrathecally injected cilnidipine showed significant analgesic effect in formalin test. Cilnidipine significantly suppressed N-type currents in dorsal root ganglion (DRG) cells. Our findings(More)
Memory function after olfactory bulbectomy (OBX) was examined in two tasks, namely, step-through passive avoidance task and elevated plus-maze task. OBX mice showed a significant impairment of learning and memory-related behavior on the 7th and 14th day, as measured by passive avoidance task but not elevated plus maze task. The impairment of learning and(More)
A significant impairment of learning and memory-related behavior was induced in mice on the 7th and 14th days after olfactory bulbectomy (OBX), as measured by a passive avoidance task. The involvement of the N-methyl-D-aspartate (NMDA) receptor ion-channel complex for learning and memory-related behavior impairment was examined by the(More)
To map the proteolytic enzymes metabolizing dynorphins in brain structures, size-exclusion chromatography linked to electrospray ionization mass spectrometry was used. Enzymes extracted from rat hippocampus, striatum, and substantia nigra were tested for their capability of converting dynorphin-related peptides. Dynorphin A was the most resistant to(More)
Intrathecal (i.t.) administration of big dynorphin (1-10 fmol), a prodynorphin-derived peptide consisting of dynorphin A and dynorphin B, to mice produced a characteristic behavioral response, the biting and/or licking of the hindpaw and the tail along with slight hindlimb scratching directed toward the flank, which peaked at 5-15 min after an injection.(More)