Dysfunctional inhibitory muscarinic receptors mediate enhanced histamine release in isolated human bronchi.

In human airways mucosal mast cells are under the control of inhibitory muscarinic receptors. The described experiments tested, whether the inhibitory potency of two muscarinic receptor agonists (oxotremorine, acetylcholine) becomes impaired in advanced chronic obstructive pulmonary disease (COPD). Isolated human bronchi obtained from 26 patients with lung cancer were separated into two groups.

Facilitation and inhibition by capsaicin of cholinergic neurotransmission in the guinea-pig small intestine.

The effects of capsaicin on [3H]acetylcholine release and muscle contraction were studied on the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum preincubated with [3H]choline. Capsaicin concentration-dependently increased both basal [3H]acetylcholine release (pEC50 7.0) and muscle tone (pEC50 6.

In vivo release of non-neuronal acetylcholine from the human skin as measured by dermal microdialysis: effect of botulinum toxin.

1.--Acetylcholine is synthesized in the majority of non-neuronal cells, for example in human skin. In the present experiments, the in vivo release of acetylcholine was measured by dermal microdialysis.

Inhibition of human detrusor contraction by a urothelium derived factor.

Purpose: Stimulating muscarinic receptors in pig bladder urothelium causes the release of a diffusable factor that inhibits contractions of the underlying detrusor muscle. We investigated whether the contractions of human detrusor strips elicited by the muscarinic agonist carbachol, electrical field stimulation, KCl or the neurokinin receptor agonist neurokinin A are affected by the urothelium.

Materials And Methods: Paired intact and urothelium denuded muscle strips were placed in modified gassed Tyrode's solution at 37C.

Effects of sex hormones, forskolin, and nicotine on choline acetyltransferase activity in human isolated placenta.

The activity of choline acetyltransferase (ChAT) was investigated in the human placenta before and after long-term incubation (24 h) to test the effects of sex hormones, nicotine and forskolin. ChAT activity differed considerably between the amnion (0.03 micromol/mg protein/h) and the villus (0.