Recent genetic analyses have revealed an important association of the gene encoding the P/Q-type voltage-dependent Ca(2+) channel alpha(1A) subunit with hereditary neurological disorders. We have identified the ataxic mouse mutation, rolling Nagoya (tg(rol)), in the alpha(1A) gene that leads to a charge-neutralizing arginine-to-glycine substitution at position 1262 in the voltage sensor-forming segment S4 in repeat III. Ca(2+) channel currents in acutely dissociated Purkinje cells, where P-type is the dominant type, showed a marked decrease in slope and a depolarizing shift by 8 mV of the conductance-voltage curve and reduction in current density in tg(rol) mouse cerebella, compared with those in wild-type. Compatible functional change was induced by the tg(rol) mutation in the recombinant alpha(1A) channel, indicating that a defect in voltage sensor of P/Q-type Ca(2+) channels is the direct consequence of the tg(rol) mutation. Furthermore, somatic whole-cell recording of mutant Purkinje cells displayed only abortive Na(+) burst activity and hardly exhibited Ca(2+) spike activity in cerebellar slices. Thus, in tg(rol) mice, reduced voltage sensitivity, which may derive from a gating charge defect, and diminished activity of the P-type alpha(1A) Ca(2+) channel significantly impair integrative properties of Purkinje neurons, presumably resulting in locomotor deficits.

BackgroundBecause the Japanese native cattle Kuchinoshima-Ushi have been isolated in a small island and their lineage has been intensely protected, it has been assumed to date that numerous and valuable genomic variations are conserved in this cattle breed.ResultsIn this study, we evaluated genetic features of this breed, including single nucleotide polymorphism (SNP) information, by whole-genome sequencing using a Genome Analyzer II. A total of 64.2 Gb of sequence was generated, of which 86% of the obtained reads were successfully mapped to the reference sequence (Btau 4.0) with BWA. On an average, 93% of the genome was covered by the reads and the number of mapped reads corresponded to 15.8-fold coverage across the covered region. From these data, we identified 6.3 million SNPs, of which more than 5.5 million (87%) were found to be new. Out of the SNPs annotated in the bovine sequence assembly, 20,432 were found in protein-coding regions containing 11,713 nonsynonymous SNPs in 4,643 genes. Furthermore, phylogenetic analysis using sequence data from 10 genes (more than 10 kbp) showed that Kuchinoshima-Ushi is clearly distinct from European domestic breeds of cattle.ConclusionsThese results provide a framework for further genetic studies in the Kuchinoshima-Ushi population and research on functions of SNP-containing genes, which would aid in understanding the molecular basis underlying phenotypic variation of economically important traits in cattle and in improving intrinsic defects in domestic cattle breeds.

Motilin and ghrelin are the gastrointestinal (GI) hormones released in a fasting state to stimulate the GI motility of the migrating motor complex (MMC). We focused on coordination of the ghrelin/motilin family in gastric contraction in vivo and in vitro using the house musk shrew (Suncus murinus), a ghrelin- and motilin-producing mammal. To measure the contractile activity of the stomach in vivo, we recorded GI contractions either in the free-moving conscious or anesthetized S. murinus and examined the effects of administration of motilin and/or ghrelin on spontaneous MMC in the fasting state. In the in vitro study, we also studied the coordinative effect of these hormones on the isolated stomach using an organ bath. In the fasting state, phase I, II, and III contractions were clearly recorded in the gastric body (as observed in humans and dogs). Intravenous infusion of ghrelin stimulated gastric contraction in the latter half of phase I and in the phase II in a dose-dependent manner. Continuous intravenous infusion of ghrelin antagonist (d-Lys3-GHRP6) significantly suppressed spontaneous phase II contractions and prolonged the time of occurrence of the peak of phase III contractions. However, intravenous infusion of motilin antagonist (MA-2029) did not inhibit phase II contractions but delayed the occurrence of phase III contractions of the MMC. In the in vitro study, even though a high dose of ghrelin did not stimulate contraction of stomach preparations, ghrelin administration (10(-10)-10(-7) M) with pretreatment of a low dose of motilin (10(-10) M) induced gastric contraction in a dose-dependent manner. Pretreatment with 10(-8) M ghrelin enhanced motilin-stimulated gastric contractions by 10 times. The interrelation of these peptides was also demonstrated in the anesthetized S. murinus. The results suggest that ghrelin is important for the phase II contraction and that coordination of motilin and ghrelin are necessary to initiate phase III contraction of the MMC.

In most animals that live in temperate regions, reproduction is under photoperiodic control. In long-day breeders such as Japanese quail and Djungarian hamsters, type 2 deiodinase (Dio2) plays an important role in the mediobasal hypothalamus, catalyzing the conversion of prohormone T4 to bioactive T3 to regulate the photoperiodic response of the gonads. However, the molecular basis for seasonal reproduction in short-day breeders remains unclear. Because thyroid hormones are also known to be involved in short-day breeders, we examined the effect of an artificial long-day stimulus on Dio2 expression in the male Saanen goat (Capra hircus), a short-day breeder. Dio2 expression was observed in the caudal continuation of the arcuate nucleus, known as the target site for both melatonin and T4 action. In addition, expression of Dio2 and T3 content in the mediobasal hypothalamus was suppressed by artificial long-day conditions, which is the opposite of the results of long-day breeders. Thyroid hormone action on the development of neuroendocrine anestrus is known to be limited to a specific seasonal window. This long-day suppression of Dio2 may provide a mechanism that accounts for the lack of responsiveness to thyroxine during the mid to late anestrus.

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