The principal voltage-sensitive sodium channel from human heart has been cloned, sequenced, and functionally expressed. The cDNA, designated hH1, encodes a 2016-amino acid protein that is homologous to other members of the sodium channel multigene family and bears greater than 90% identity to the tetrodotoxin-insensitive sodium channel characteristic of rat heart and of immature and denervated rat skeletal muscle. Northern blot analysis demonstrates an approximately 9.0-kilobase transcript expressed in human atrial and ventricular cardiac muscle but not in adult skeletal muscle, brain, myometrium, liver, or spleen. When expressed in Xenopus oocytes, hH1 exhibits rapid activation and inactivation kinetics similar to native cardiac sodium channels. The single channel conductance of hH1 to sodium ions is about twice that of the homologous rat channel and hH1 is more resistant to block by tetrodotoxin (IC50 = 5.7 microM). hH1 is also resistant to mu-conotoxin but sensitive to block by therapeutic concentrations of lidocaine in a use-dependent manner.
Pharmacology, Toxicology and Pharmaceutical Science
7
4%
Other
9
5%
Unknown
50
28%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 12. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 02 January 2026.
All research outputs
#3,807,781
of 34,545,128 outputs
Outputs from Proceedings of the National Academy of Sciences of the United States of America
#39,146
of 119,135 outputs
Outputs of similar age
#2,790
of 89,006 outputs
Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#29
of 396 outputs
Altmetric has tracked 34,545,128 research outputs across all sources so far. Compared to these this one has done well and is in the 88th percentile: it's in the top 25% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 119,135 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 40.1. This one has gotten more attention than average, scoring higher than 64% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 89,006 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 95% of its contemporaries.
We're also able to compare this research output to 396 others from the same source and published within six weeks on either side of this one. This one has done well, scoring higher than 85% of its contemporaries.
