Nav'

The Nawie or Nawki in Polish, the Mavka (Navka, Nyavka, Zalozhnі mertsі) in Ukrainian, or simply Nav' in other Slavic languages are ghosts or the souls of persons that had met a tragic or premature death, particularly unchristened babies. In Slavic mythology, Nawie exist in the underworld called Nawia.

In Ukrainian mythology, Mavka is a type of mermaids with long flaxen hair. The name Mavka derives from Nav’ (Navka), which means "the embodiment of death." Mavky (plural) do not have a full body, have no reflection in water, do not cast shadows, and have no back, and so their insides can be seen.

The traditional view is that Mavky live in the woods of Galicia (Ukraine) and the Carpathians. Mavky symbolize the souls of children who were born dead or died unbaptized. They often appear in the form of beautiful young girls dancing and singing to lure young men into the woods where they would tickle them to death and chop their heads off.

To save a baby's soul, one had to throw up a kerchief during Trinity holidays, say a name and add "I baptize you". A rescued soul would then go to heaven. If a soul lived up to seven years and did not go to heaven, a baby would turn into a mermaid or a Mavka and would haunt people.

NAV

NAV or Nav may refer to:

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Nav1.7

Na_v1.7 is a sodium ion channel that in humans is encoded by the SCN9A gene. It is usually expressed at high levels in two types of neurons, the nociceptive (pain) neurons at dorsal root ganglion (DRG) and trigeminal ganglion, and sympathetic ganglion neurons, which are part of the autonomic (involuntary) nervous system.

Function

Na_v1.7 is a voltage-gated sodium channel and plays a critical role in the generation and conduction of action potentials and is thus important for electrical signaling by most excitable cells. Na_v1.7 is present at the endings of pain-sensing nerves, the nociceptors, close to the region where the impulse is initiated. Stimulation of the nociceptor nerve endings produces "generator potentials", which are small changes in the voltage across the neuronal membranes. The Na_v1.7 channel amplifies these membrane depolarizations, and when the membrane potential difference reaches a specific threshold, the neuron fires. In sensory neurons, multiple voltage-dependent sodium currents can be differentiated by their voltage dependence and by sensitivity to the voltage-gated sodium-channel blocker tetrodotoxin. The Na_v1.7 channel produces a rapidly activating and inactivating current which is sensitive to the level of tetrodotoxin. Na_v1.7 is important in the early phases of neuronal electrogenesis. Na_v1.7 activity consists of a slow transition of the channel into an inactive state when it is depolarized, even to a minor degree. This property allows these channels to remain available for activation with even small or slowly developing depolarizations. Stimulation of the nociceptor nerve endings produces "generator potentials", small changes in the voltage across the neuronal membranes. This brings neurons to a voltage that stimulate Na_v1.8, which has a more depolarized activation threshold that produces most of the transmembrane current responsible for the depolarizing phase of action potentials.

Nav1.8

Na_v1.8 is a sodium ion channel that in humans is encoded by the SCN10A gene. Na_v1.8 is a sodium channel subunit.

Na_v1.8 is a tetrodotoxin (TTX)-resistant voltage-gated sodium ion channel. It is expressed specifically in the dorsal root ganglion (DRG), in unmyelinated, small-diameter sensory neurons called C-fibres and is involved in the pain pathway called nociception. C-fibres can be activated by noxious thermal or mechanical stimuli and thus can carry pain messages.

The discrete locations of Na_v1.8 in sensory neurons of the DRG may be the key factor in therapeutic targets for the development of new analgesics and to treat chronic pain.

Function

Voltage-gated sodium ion channels (VGSC) are essential in producing and propagating action potentials. Tetrodotoxin, a toxin found in pufferfish is able to block some VGSCs and therefore is used to distinguish the different subtypes. There are three TTX-resistant VGSC: Na_v1.5, Na_v1.8 and Na_v1.9. Na_v1.8 and Na_v1.9 are both expressed in nociceptors (damage-sensing neurons). It is known that Na_v1.7, Na_v1.8 and Na_v1.9 are located in the DRG and play an important role in maintaining chronic inflammatory pain.

Nav1.1

Na_v1.1, also known as the sodium channel, voltage-gated, type I, alpha subunit (SCN1A), is a protein which in humans is encoded by the SCN1A gene.

Function

The vertebrate sodium channel is a voltage-gated ion channel essential for the generation and propagation of action potentials, chiefly in nerve and muscle. Voltage-sensitive sodium channels are heteromeric complexes consisting of a large central pore-forming glycosylated alpha subunit and 2 smaller auxiliary beta subunits. Functional studies have indicated that the transmembrane alpha subunit of the brain sodium channels is sufficient for expression of functional sodium channels. Brain sodium channel alpha subunits form a gene subfamily with several structurally distinct isoforms clustering on chromosome 2q24, types I, II (Na_v1.2), and III (Na_v1.3). There are also several distinct sodium channel alpha subunit isoforms in skeletal and cardiac muscle (Na_v1.4 and Na_v1.5, respectively).

Clinical significance

Mutations in the SCN1A gene cause inherited febrile seizures and GEFS+, type 2.

NAV1

Neuron navigator 1 is a protein that in humans is encoded by the NAV1 gene.

This gene belongs to the neuron navigator family and is expressed predominantly in the nervous system. The encoded protein contains coiled-coil domains and a conserved AAA domain characteristic for ATPases associated with a variety of cellular activities. This gene is similar to unc-53, a Caenorhabditis elegans gene involved in axon guidance. The exact function of this gene is not known.

References

Further reading