Abnormal angiogenesis and responses to glucose and oxygen deprivation in mice lacking the protein ARNT

Article Abstract:

Arylhydrocarbon-receptor nuclear translocator(super -1-) (ARNT(super -1-))embryonic stem cells fail to activate genes that usually respond to low oxygen tension as well as fail to respond to a decline in glucose concentration. This suggests that ARNT is essential in the response to hypoxia and hypoglycaemia. ARNT(super -1-) embryos were not viable beyond embryonic day 10.5 and exhibited abnormal angiogenesis of the yolk sac and branchial arches, retarded development and lethal embryo wasting. Based on these, a model is proposed wherein local hypoxic and hypoglycaemic conditions stimulate ARNT transcriptional activity during organogenesis, causing VEGF and tissue factor production and blood vessel development.

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Reduced vas deferens contraction and male infertility in mice lacking P2X1 receptors

Article Abstract:

It has been established that P2X1 receptors for ATP are involved in the contraction of the vas deferens in mice. Male fertility is reduced by around 90% in mice with a targeted deletion of the P2X1 receptor gene. This is the result of a reduction in sperm in the ejaculate connected with a drop in neurogenic vas deferens contraction. The physiological sympathetic nerve firing pattern leading to ejaculation has not yet been determined. The burst of sympathetic nerve activity to the vas deferens linked with ejaculation is probably substantially shorter than the duration of copulation.

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Coexpression of P2X(sub 2) and P2X(sub 3) receptor subunits can account for ATP-gated currents in sensory neurons

Article Abstract:

Cloning of P2X(sub 3) from the dorsal-root-ganglion sensory neurons of rat reveals that the ATP-gated channels establish distinct heteropolymerization of P2X receptor subunits. The specific subunit formation of the P2X receptor probably generates a phenotype conforming to the function of ATP in primary afferent neurotransmission. Coexpression of P2X(sub 2) and P2X(sub 3) generates ATP-gated currents identical to those in sensory neurons.

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