We investigated the role of large-conductance Ca(2+)-activated K(+) (BK) channels in beta3-adrenoceptor (beta3-AR)-induced relaxation in rat urinary bladder smooth muscle (UBSM). BRL 37344, a specific beta3-AR agonist, inhibits spontaneous contractions of isolated UBSM strips. SR59230A, a specific beta3-AR antagonist, and H89, a PKA inhibitor, reduced the inhibitory effect of BRL 37344. Iberiot...

The physiological functions of the urinary bladder are to store and periodically expel urine. These tasks are facilitated by the contraction and relaxation of the urinary bladder smooth muscle (UBSM), also known as detrusor smooth muscle, which comprises the bladder wall. The large-conductance voltage- and Ca(2+)-activated K(+) (BK, BKCa, MaxiK, Slo1, or KCa1.1) channel is highly expressed in U...

Large conductance calcium- and voltage-gated potassium (BK) channels are important regulators of physiological homeostasis and their function is potently modulated by protein kinase A (PKA) phosphorylation. PKA regulates the channel through phosphorylation of residues within the intracellular C terminus of the pore-forming alpha-subunits. However, the molecular mechanism(s) by which phosphoryla...

The large conductance, calcium-activated (BK-type) potassium channels are regulators of voltage-dependent calcium entry in many cell types. The BK channel accessory β1 subunit promotes channel activation in smooth muscle and is required for proper tone in the vasculature and bladder. However, although BK channels have also been implicated in airway smooth muscle function, their regulation by th...

Large conductance Ca2+-activated K+ (BK) channels belong to the S4 superfamily of K+ channels that include voltage-dependent K+ (Kv) channels characterized by having six (S1-S6) transmembrane domains and a positively charged S4 domain. As Kv channels, BK channels contain a S4 domain, but they have an extra (S0) transmembrane domain that leads to an external NH2-terminus. The BK channel is activ...

Intellectual disability (ID), one of the most common human developmental disorders, can be caused by genetic mutations in Cullin 4B (Cul4B) and cereblon (CRBN). CRBN is a substrate receptor for the Cul4A/B-DDB1 ubiquitin ligase (CRL4) and can target voltage- and calcium-activated BK channel for ER retention. Here we report that ID-associated CRL4CRBN mutations abolish the interaction of the BK ...

The pharmacology of the large-conductance K(+) (BK) channel in human osteoblasts is not well defined, and its role in bone is speculative. Here we assess BK channel properties in MG63 cells and primary human osteoblasts and determine whether pharmacological modulation affects cell function. We used RT-PCR and patch-clamp methods to determine the expression of BK channel subunits and cell number...

Large-conductance Ca2+- and voltage-activated potassium (BK) channels are widely expressed in tissues. As a voltage and calcium sensor, BK channels play significant roles in regulating the action potential frequency, neurotransmitter release, and smooth muscle contraction. After associating with the auxiliary β2 subunit, mammalian BK(β2) channels (mouse or human Slo1/β2) exhibit enhanced activa...

Malysz J, Afeli SA, Provence A, Petkov GV. Ethanol-mediated relaxation of guinea pig urinary bladder smooth muscle: involvement of BK and L-type Ca channels. Am J Physiol Cell Physiol 306: C45–C58, 2014. First published October 23, 2013; doi:10.1152/ajpcell.00047.2013.—Mechanisms underlying ethanol (EtOH)-induced detrusor smooth muscle (DSM) relaxation and increased urinary bladder capacity rem...

The large-conductance, Ca2+-activated K+ (BK) channels are regulators of voltage-dependent Ca2+ entry in many cell types. The BK channel accessory beta1-subunit promotes channel activation in smooth muscle and is required for proper tone in the vasculature and bladder. However, although BK channels have also been implicated in airway smooth muscle function, their regulation by the beta1-subunit...