K7 channels modulate tension and calcium signalling in mouse corpus cavernosum.

Adrenergic stimulation induces contractions in the corpus cavernosum smooth muscle (CCSM) that are important in maintaining penile flaccidity. The aim of this study was to investigate the role of K7 channels in regulating contractions and their underlying Ca signals in mouse CCSM. Quantitative PCR revealed transcriptional expression of KCNQ1 and KCNQ3-5 genes in whole CCSM, with KCNQ5 as the most highly transcribed K7 encoding gene.

Role of voltage-gated Ca channels and Ano1 Ca-activated Cl channels in M2 muscarinic receptor-dependent contractions of murine airway smooth muscle.

Cholinergic tone is elevated in obstructive lung conditions such as COPD and asthma, but the cellular mechanisms underlying cholinergic contractions of airway smooth muscle (ASM) are still unclear. Some studies report an important role for L-type Ca channels (LTCC) and Ano1 Ca-activated Cl™ channels (CACC) in these responses, but others dispute their importance. Cholinergic contractions of ASM involve activation of M3Rs, however stimulation of M2Rs exerts a profound hypersensitisation of these responses.

Evidence of an excitatory purinergic innervation in mouse corpus cavernosum smooth muscle.

Background: Evidence suggests that the corpus cavernosum smooth muscle (CCSM) cells of several species, including humans, express purinergic P2X receptors, but it is not known if the corpus cavernosum has an excitatory purinergic innervation.

Aim: In this study we aimed to determine if the mouse CCSM has a functional purinergic innervation.

Methods: Mouse CCSM myocytes were enzymatically isolated and studied using the perforated patch configuration of the patch clamp technique.

Interstitial cell of Cajal-like cells (ICC-LC) exhibit dynamic spontaneous activity but are not functionally innervated in mouse urethra.

Urethral smooth muscle cells (USMC) contract to occlude the internal urethral sphincter during bladder filling. Interstitial cells also exist in urethral smooth muscles and are hypothesized to influence USMC behaviours and neural responses. These cells are similar to Kit interstitial cells of Cajal (ICC), which are gastrointestinal pacemakers and neuroeffectors.

Regulation of nerve-evoked contractions of the murine vas deferens.

Stimulation of sympathetic nerves in the vas deferens yields biphasic contractions consisting of a rapid transient component resulting from activation of P2X1 receptors by ATP and a secondary sustained component mediated by activation of α-adrenoceptors by noradrenaline. Noradrenaline can also potentiate the ATP-dependent contractions of the vas deferens, but the mechanisms underlying this effect are unclear. The purpose of the present study was to investigate the mechanisms underlying potentiation of transient contractions of the vas deferens induced by activation of α-adrenoceptors.