D1

D1 is an alphanumeric designation applied across various domains rather than a single entity. The meaning depends on context.

In biology and pharmacology, D1 refers to the dopamine receptor D1, a G-protein-coupled receptor that binds dopamine and belongs to the D1-like family. It is expressed in brain regions such as the striatum and is implicated in motor function, reward, and cognition. The DRD1 gene encodes the receptor.

In video and broadcasting technology, D-1 (or D1) denotes a professional digital component video format introduced in the late 1980s. It records uncompressed video using 4:2:2 sampling and 10-bit depth, typically for standard-definition signals (NTSC/PAL). It served as a standard for digital studio workflows before later formats supplanted it.

In infrastructure and transportation, D1 is a common designation for regional or departmental roads in several countries, including France and others; such roads connect major towns and serve as important links within national networks.

Other uses include model names, product codes, or project identifiers across different industries; the precise meaning of D1 depends on the field and the context in which it appears.