1. The hypothesis that inward rectifier K+ channels are involved in the vasodilatation of small coronary and cerebral arteries (100-200 ,um diameter) in response to elevated [K+]. was tested. The diameters and membrane potentials of pressurized arteries from rat were measured using a video-imaging system and conventional microelectrodes, respectively. 2. Elevation of [K+]o from 6 to 16 mm caused the membrane potential of pressurized (60 mmHg) arteries to hyperpolarize by 12-14 mV. Extracellular Ba2P (Ba20+) blocked K+-induced membrane potential hyperpolarizations at concentrations (IC50, 6 uM) that block inward rectifier K+ currents in smooth muscle cells isolated from these arteries. 5. These findings suggest that K+ dilates small rat coronary and cerebral arteries through activation of inward rectifier K+ channels. Furthermore, these results support the hypothesis that inward rectifier K+ channels may be involved in metabolic regulation of coronary and cerebral blood flow in response to changes in [K+]0.

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Abstract. This paper reports on the factorization of the 768-bit number RSA-768 by the number field sieve factoring method and discusses some implications for RSA.