Septo-hippocampal cholinergic fibres ramify extensively throughout the hippocampal formation to release acetylcholine upon a diverse range of muscarinic and nicotinic acetylcholine receptors that are differentially expressed by distinct populations of neurones. The resultant modulation of cellular excitability and synaptic transmission within hippocampal circuits underlies the ability of acetyl...

BACKGROUND An imbalance of sympathetic and parasympathetic drive to the heart is an important risk factor for cardiac death in patients with coronary heart disease, diabetes, and renal insufficiency. The amount of neurotransmitter released from peripheral autonomic nerves is modulated by presynaptic receptor systems. In analogy to alpha-autoreceptors on sympathetic nerves, muscarinic autorecept...

Muscarinic receptors are widely spread throughout the body, and are involved in the regulation of fundamental physiological processes, like the modulation of the heart rate, control of motor systems and modulation of learning and memory. In the central nervous system the cholinergic transmission is mainly mediated by muscarinic receptors; there are five subtypes that are all expressed in the br...

G protein-coupled receptors (GPCRs) are the largest family of signaling proteins and the most common therapeutic targets. In the last 2 decades, impressive progress in the understanding of GPCR function has been achieved, driven largely by the idea of similarity of the molecular mechanisms underlying their signaling and regulation. However, recent comprehensive studies of signaling and traffick...

A proper balance between striatal muscarinic cholinergic and dopaminergic neurotransmission is required for coordinated locomotor control. Activation of striatal muscarinic acetylcholine receptors (mAChRs) is known to modulate striatal dopamine release. To identify the mAChR subtype(s) involved in this activity, we used genetically altered mice that lacked functional M1-M5 mAChRs [knock-out (KO...

Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation caused by persistent inflammatory processes in the airways. An increased cholinergic tone mediates different pathophysiological features of COPD, such as bronchoconstriction and mucus hypersecretion, mostly through activation of the human muscarinic M(3) receptor (hM(3)) subtype. Tiotropium bromide (...

We have evaluated the muscarinic acetylcholine family of G protein-coupled receptors (mAChRs) for their oncogenic potential. These receptors are preferentially expressed in postmitotic cells, transducing signals specified by their endogenous agonist, the neurotransmitter acetylcholine. Cells transfected with individual human mAChR genes were morphologically indistinguishable from parental NIH 3...

The role of muscarinic (M)-receptor subtypes in the regulation of vascular tone has not yet been defined in humans. To analyze the role of M-receptor subtypes in the forearm resistance vasculature of normotensive volunteers (n = 20), we infused acetylcholine (ACh) and methacholine (MCh) in the presence of saline and the antagonists atropine (nonselective), pirenzepine (M1 selective), and AF-DX ...