We detect HCN J=5-4 emission from the ultraluminous quasar APM08279+5255 at z=3.911 using the IRAM Plateau de Bure interfer-ometer. This object is strongly gravitationally lensed, yet still thought to be one of the most intrinsically luminous objects in the Universe. The new data imply a line luminosity L ′ HCN (J=5−4) = 4.0 ± 0.5 × 10 10 K km s −1 pc 2. The ∼ 440 km s −1 full width half maximu...

Hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels are expressed in several tissues throughout the body, including the heart, the CNS, and the retina. HCN channels are found in many neurons in the retina, but their most established role is in generating the hyperpolarization-activated current, I(h), in photoreceptors. This current makes the light response of rod and cone pho...

Hydrogen cyanide (HCN) is a ubiquitous molecule in the Universe. It is a compound that is easily produced in significant yields in prebiotic simulation experiments using a reducing atmosphere. HCN can spontaneously polymerise under a wide set of experimental conditions. It has even been proposed that HCN polymers could be present in objects such as asteroids, moons, planets and, in particular, ...

The hyperpolarization-activated/cyclic nucleotide (HCN)-gated channels make important contributions to neural excitability. In prefrontal cortex, HCN channels are localized on the distal dendrites of layer V pyramidal neurons and decrease neural excitability when they are open. In the present study, using whole-cell voltage clamp recordings, the effect of an arousal peptide, orexin A, on HCN cu...

We have calculated an ab initio HCN/HNC linelist for all transitions up to J=25 and 18000 cm above the zero point energy. This linelist contains more than 200 million lines each with frequencies and transition dipoles. The linelist has been calculated using our semi-global HCN/HNC VQZANO+PES and dipole moment surface, which were reported in van Mourik et al. (J. Chem. Phys. 115 (2001) 3706). Wi...

Hyperpolarization-activated, cyclic nucleotide-gated cation (HCN) channels are expressed postsynaptically in the rodent globus pallidus (GP), where they play several important roles in controlling GP neuronal activity. To further elucidate the role of HCN channels in the GP, immunocytochemical and electrophysiological approaches were used to test the hypothesis that HCN channels are also expres...

Hyperpolarization-activated pacemaker currents (I(H)) contribute to the subthreshold properties of excitable cells and thereby influence behaviors such as synaptic integration and the appearance and frequency of intrinsic rhythmic activity. Accordingly, modulation of I(H) contributes to cellular plasticity. Although I(H) activation is regulated by a plethora of neurotransmitters, including some...

Cyanogenesis denotes a chemical defensive strategy where hydrogen cyanide (HCN, hydrocyanic or prussic acid) is produced, stored, and released toward an attacking enemy. The high toxicity and volatility of HCN requires both chemical stabilization for storage and prevention of accidental self-poisoning. The few known cyanogenic animals are exclusively mandibulate arthropods (certain myriapods an...

Hyperpolarization-activated Cyclic Nucleotide (HCN) channels are voltage-gated cation channels and are critical for regulation of membrane potential in electrically active cells. To understand the evolution of these channels at the molecular level, we cloned and examined two of three HCN homologs of the urochordate Ciona intestinalis (ciHCNa and ciHCNb). ciHCNa is like mammalian HCNs in that it...

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are key modulators of neuronal activity by providing the depolarizing cation current I(h) involved in rhythmogenesis, dendritic integration, and synaptic transmission. These tasks critically depend on the availability of HCN channels, which is dynamically regulated by intracellular cAMP; the range of this regulation, however, la...