Help with Neurotransmitter and Receptor Physiology

Muscarinic acetylcholine receptors (mAChRs) are found in the G protein-receptor complexes in the cell membrane of certain neurons. The suffix -ergic means exhibiting or stimulating the activity of. For example, dopaminergic receptors bind to dopamine.

Norepinephrine is released by adrenergic neurons.

Cholinergic neurons release acetylcholine as their neurotransmitter (in the sympathetic or parasympathetic nervous system).

Nonadrenergic, noncholinergic neurons (which include postganglionic parasympathetic neurons of the gastrointestinal tract) release substance P and nitric oxide.

Acetylcholine is the neurotransmitter found at the neuromuscular junction and many other synapses found in the nervous system. It binds to receptors on the postsynaptic membrane to induce muscular contraction.

GABA is the most common inhibitory neurotransmitter in the brain. Glutamate is the most common excitatory neurotransmitter in the brain. Dopamine is a monoamine which can sometimes be inhibitory, but is not the most common.

The substantia nigra is composed of primarily dopamine. When the substantia nigra is effected by a disease, a patient can present with Parkinson-like symptoms. Most common symptom is resting tremors.

Acetylcholine activates muscarinic receptors in postganglioinic parasympathetic nervous tissue and nicotinic receptors in skeletal muscle fibers, and preganglionic sympathetic and parasympathetic nervous tissue.

Nociceptors are pain receptors that. Mechanoreceptors respond when tissue is deformed by mechanical forces. Photoreceptors respond to light. Chemoreceptors respond to chemicals. Thermoreceptors respond to changes in temperature.

Neurotransmitters are packaged in vesicles, traveling through the synaptic cleft (space between neurons) from the pre-synaptic membrane to the post-synaptic membrane, where they bind to their receptors and influence the post-synaptic membrane potential.

Glutamic acid is an excitatory neurotransmitter. During a cerebrovascular accident, cells that have died due to oxygen deprivation release large quantities of glutamic acid. This causes surrounding cells to become overexcited and eventually die. This process is called excitotoxicity.

Opioid neuroactive peptides include enkephalins, endorphins, and dynorphin. These bind to opiate receptors in the brain, which also bind opiate drugs such as heroin and morphine. These are known to play a role in response to injury stress and pain perception and are released during exercise. Non-opioid neuroactive peptides do not bind opiates and their function is not well understood. Amino acids include glutamic acid and GABA. Biogenic amines include monoamines and catecholamines, which include norepinephrine, epinephrine, dopamine, and serotonin.