Muscarinic Cholinoreceptors in Skeletal Muscle: Localization and Functional Role.

The review focuses on the modern concepts of the functions of muscarinic cholinoreceptors in skeletal muscles, particularly, in neuromuscular contacts, and that of the signaling pathways associated with the activation of various subtypes of muscarinic receptors in the skeletal muscles of cold-blooded and warm-blooded animals. Despite the long history of research into the involvement of muscarinic receptors in the modulation of neuromuscular transmission, many aspects of such regulation and the associated intracellular mechanisms remain unclear. Now it is obvious that the functions of muscarinic receptors in skeletal muscle are not limited to the autoregulation of neurosecretion from motor nerve endings but also extend to the development and morphological rearrangements of the synaptic apparatus, coordinating them with the degree of activity.

Role of α7 Nicotinic Acetylcholine Receptors in Synaptic Transmission in Frog Neuromuscular Contacts.

The role of α7 nicotinic acetylcholine receptors in coupling of synaptic activity and muscle contractions was studied in frog (Rana ridibunda) neuromuscular synapses. The amplitude of endplate currents, the probability of action potential generation, and the strength of muscle contractions decreased in the presence of selective α7 antagonist methyllycaconitine. The effects of nicotinic acetylcholine receptor blockade depended on the pattern of the motor nerve stimulation.

GIRK channel as a versatile regulator of neurotransmitter release via L-type Ca channel-dependent mechanism in the neuromuscular junction.

G protein-gated inwardly rectifying potassium (GIRK) channels are one of the main regulators of neuronal excitability. Activation of GIRK channels in the CNS usually leads to postsynaptic inhibition. However, the function of GIRK channels in the presynaptic processes, notably neurotransmitter release form motor nerve terminals, is yet to be comprehensively understood.

Adrenergic receptors control frequency-dependent switching of the exocytosis mode between "full-collapse" and "kiss-and-run" in murine motor nerve terminal.

Aims: Neurotransmitter release from the synaptic vesicles can occur through two modes of exocytosis: "full-collapse" or "kiss-and-run". Here we investigated how increasing the nerve activity and pharmacological stimulation of adrenoceptors can influence the mode of exocytosis in the motor nerve terminal.

Methods: Recording of endplate potentials with intracellular microelectrodes was used to estimate acetylcholine release.