Urinary bladder function and somatic sensitivity in vasoactive intestinal polypeptide (VIP)-/- mice.

Vasoactive intestinal polypeptide (VIP) is an immunomodulatory neuropeptide widely distributed in neural pathways that regulate micturition. VIP is also an endogenous anti-inflammatory agent that has been suggested for the development of therapies for inflammatory disorders. In the present study, we examined urinary bladder function and hindpaw and pelvic sensitivity in VIP(-/-) and littermate wildtype (WT) controls.

Apical epidermal growth factor receptor signaling: regulation of stretch-dependent exocytosis in bladder umbrella cells.

The apical surface of polarized epithelial cells receives input from mediators, growth factors, and mechanical stimuli. How these stimuli are coordinated to regulate complex cellular functions such as polarized membrane traffic is not understood. We analyzed the requirement for growth factor signaling and mechanical stimuli in umbrella cells, which line the mucosal surface of the bladder and dynamically insert and remove apical membrane in response to stretch.

ATP and purinergic receptor-dependent membrane traffic in bladder umbrella cells.

The umbrella cells that line the bladder are mechanosensitive, and bladder filling increases the apical surface area of these cells; however, the upstream signals that regulate this process are unknown. Increased pressure stimulated ATP release from the isolated uroepithelium of rabbit bladders, which was blocked by inhibitors of vesicular transport, connexin hemichannels, ABC protein family members, and nucleoside transporters. Pressure-induced increases in membrane capacitance (a measure of apical plasma membrane surface area where 1 microF approximately equals 1 cm2) were inhibited by the serosal, but not mucosal, addition of apyrase or the purinergic receptor antagonist PPADS.

Estrous cycle influences on sexual diergism of HPA axis responses to cholinergic stimulation in rats.

Central cholinergic systems differentially modulate hypothalamic-pituitary-adrenal (HPA) axis activity in female and male animals (sexual diergism). We previously reported that male rats had significantly greater HPA axis responses to stimulation by physostigmine (PHYSO), an acetylcholinesterase (AChE) inhibitor, compared to females. Females in defined estrous cycle stages, however, were not studied because of sample size limitations.