____ ____ in the spinal-cord have one branch to the muscles, where they release acetylcholine, and another branch to other spinal-cord neurons, where they release both acetylcholine and glutamate.
A combination of transmitters makes the neurons message more ____, such as brief excitation followed by slight but prolonged inhibition.
Although a neuron releases only a limited number of neurotransmitters, it may receive and respond to many neurotransmitters at different ____.
The effect of a neurotransmitter depends on its receptor on the postsynaptic cell. When the neurotransmitter attaches to its receptor, the receptor may open a channel – exerting an ____ effect – or it may produce a slower but longer effect – a ____ effect.
ionotropic : metabotropic
Imagine a paper bag that is twisted shut at the top. If you untwist it, the opening grows larger to that something can go into or come out of the bag. An ____ ____ is like that.
When the neurotransmitter binds to an ionotropic receptor, it twists the receptor enough to open a ____ ____, which is shaped to let a particular type of ion pass through.
Channels controlled by neurotransmitter are _____ or _____ channels. That is, when the neurotransmitter attaches, it opens a channel. (A ligand is a chemical that binds to another chemical.)
transmitter-gated or ligand-gated
Ionotropic effects are well suited to convey ____ information, ____ information, and anything else that needs to be updated as quickly as possible.
visual : auditory
Most of the brains excitatory ionotropic synapses use the neurotransmitter ____.
Most of the inhibitory ionotropic synapses use the neurotransmitter GABA (__________), which opens chloride gates, enabling chloride ions, with the negative charge, to cross the membrane into the cell more rapidly than usual.
____ is another common inhibitory transmitter, found mostly in the spinal cord.
____, another transmitter at many ionotropic synapses, is excitatory in most cases.
At other receptors, neurotransmitters exert ____ ____ by initiating sequence of metabolic reactions that are slower and longer lasting than ionotropic effects.
Metabotropic synapses use many neurotransmitters, including ____, ____, and ____… and sometimes glutamate and GABA too.
dopamine, norepinephrine, and serotonin
When neurotransmitters attaches to metabotropic receptor, it ____ the receptor protein that goes through the membrane of the cell.
The other side of the bent receptor is attached to a ____ – that is, a protein coupled to ____ ____ (GTP), an energy storing molecule.
G protein : guanosine triphosphate
Bending the receptor protein ____ that G protein, which is then free to take energy elsewhere in the cell.
Metabotropic synapses are better suited for more enduring effects such as ____, ____, and ____, where exact timing isn't important anyway.
taste, smell, and pain
Metabotropic synapses are also important for many aspects of ____, ____, ____, and ____ – again, functions that arise more slowly and last longer than visual or auditory stimulus.
arousal, attention, pleasure, and emotion
Research is often refer to neuropeptides as ____, because they have several properties that set them apart from other transmitters.
Where as the neuron synthesises most other neurotransmitters in the presynaptic terminal, it synthesises neuropeptides in the ____ ____ and then slowly transports them to other parts of the cell.
Whereas other neurotransmitters are released at the axon terminal, neuropeptides are released mainly by ____.
Neurons containing neuropeptides do not often release them, but when they do, they release ____ amounts.
Neuropeptides are important for ____, ____, ____ ____, and other long-term changes in behaviour and experience.
hunger, thirst, intense pain
A ____ is a chemical that is secreted by cells in one part of the body and conveyed by the blood to the other cells.
A neurotransmitter is it like a telephone signal: it conveys a message from the sender to the intended receiver. Hormones function more like a ____ ____: they convey a message to any receiver tuned into the right station.
A receptor known as an ____ is a receptor that responds to the released transmitter by inhibiting further synthesis and release. That is, they provide negative feedback.
Some postsynaptic neurons respond to stimulation by releasing special chemicals that travel back to the presynaptic terminal, where they ____ further release of transmitters.
At an electrical synapse, the membrane of one neuron comes into direct contact with the membrane of another, this contact is called a ___ ____.