The P/Q-type channels, also known as α1A or Cav2.1, are high voltage activated (HVA) calcium channels widespread throughout cortex. They function in both vesicle release and postsynaptic calcium entry. The α1 subunit is a principal subunit, localized in the cell membrane and forming a conductive pore. β, α2, δ, and γ are auxiliary subunits.
The β subunits are believed to enhance the trafficking of the channels to the plasma membrane by binding via their guanylate kinase (GK)-like domain to the a interaction domain (AID) on the I–II linker of all theHVAa subunits .
See also the Channelpedia entry for Cav2.2 which is similar to Cav2.1 in many respects.
Genbank 25398, Cacna1a calcium channel, voltage-dependent, P/Q type, alpha 1A subunit [ Rattus norvegicus ], also known as BccA1; rbA-1; Cav2.1; Cacna1a
The alpha 2.1 (alpha 1A) subunits of P-type and Q-type Ca 2+
channels are encoded by a single gene, Cacna1a. 
Double layer of lipid molecules that encloses all cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins.
G proteins, calmodulin
High sensitivity to the funnel web spider venom Omega-agatoxin-IVA. Mintz 
Roscovitine, a potent inhibitor of cyclin-dependent kinases 1, 2, and 5, slows the deactivation of P/Q (Cav2.2) and N-type (CaV2.1) calcium channels. 
When compared with other Ca channels, the Cav2.1 (rbA) channel is notably different in both the carboxyl terminus and in a large (474-amino acid) hydrophilic segment between domains II and HI. 
CaV 2.1 channels are widely distributed in the presynaptic
terminals and somatodendritic membranes throughout the brain .
Predominantly expressed in the cerebellar Purkinje cells and
granule cells .
P/Q-type calcium channels (Cav2.1) play an important role in mediating neurotransmitter release in the nervous system, postsynaptic integration, neuroplasticity, neural excitability, and gene transcription , , .
Malfunction of Cav2.1 brings about the disease spinocerebellar ataxia type 6. .
Mutations in the gene encoding the pore-forming α1A subunit of P/Q Ca2+ channels (CACNA1A) are linked to familial hemiplegic migraine. 
The most detailed model can be found in . It is from hippocampal mossy fiber boutons.
A detailed compartmental model of a Purkinje neuron, taking into account two types of low-threshold Ca 21 channel (T-type and class-E, or R-type) and two types of low-threshold K 1 channel (A-type and D-type), in addition to another eight voltage-gated channel types, using the program NEURON.