Study Set Content:
Indirectly acting and mixed sympathomimetics: Ex:
Tyramine
• Amphetamines
• Ephedrine
Are capable of releasing stored transmitter from noradrenergic nerve endings by a calciumin dependent process.
Indirectly acting and mixed sympathomimetics
These drugs are poor (blank) (some are inactive) at adrenoceptors, but they are excellent (blank) for monoamine transporters.
agonists, substrates
Termination of noradrenergic transmission results from two processes:
1. Simple diffusion away from the receptor site (with eventual metabolism in the plasma or liver)
2. Reuptake into the nerve terminal by NET or into perisynaptic or other cells
The vesicles of both cholinergic and adrenergic nerves contain other substances in addition to the primary transmitter, sometimes in the same vesicles and sometimes in a separate vesicle population.
The vesicles of both cholinergic and adrenergic nerves contain other substances in addition to the primary transmitter, sometimes in the same vesicles and sometimes in a separate vesicle population.
Many of these substances are also (blank) in the nonadrenergic, noncholinergic nerves. They appear to play several roles in the function of nerves that release acetylcholine or norepinephrine.
primary transmitters
In some cases, they provide a (blank) action to supplement or modulate the effects of the primary transmitter. They also participate in feedback inhibition of the same and nearby nerve terminals.
faster or slower
The primary transmitter at ANS ganglia, at the somatic neuromuscular junction, and at parasympathetic postganglionic nerve endings
Acetylcholine (ACh)
A primary excitatory transmitter to smooth muscle and secretory cells in the ENS.
Acetylcholine (ACh)
Acts as a transmitter or cotransmitter at many ANS-effector synapses
Adenosine triphosphate (ATP)
Probably also the major neuron-to-neuron (“ganglionic”) transmitter in the ENS.
Acetylcholine (ACh)
Found with substance P in cardiovascular sensory nerve fibers. Present in some secretomotor ENS neurons and interneurons. A cardiac stimulant.
Calcitonin gene-related peptide (CGRP)
A modulatory transmitter in some ganglia and the ENS. Possibly a postganglionic sympathetic transmitter in renal blood vessels.
Dopamine
May act as a cotransmitter in some excitatory neuromuscular ENS neurons
Cholecystokinin (CCK)
Present in some secretomotor and interneurons in the ENS.
Enkephalin and related opioid peptides
Appear to inhibit ACh release and thereby inhibit peristalsis.
Enkephalin and related opioid peptides
May stimulate secretion.
Enkephalin and related opioid peptides
May have presynaptic effects on excitatory ENS nerve terminals. Has some relaxant effect on the gut. Probably not a major transmitter in the ENS
GABA (γ-aminobutyric acid)
Present in secretomotor neurons; may play a role in appetite-satiety mechanisms.
Galanin
Extremely potent excitatory transmitter to gastrin cells
Gastrin-releasing peptide (GRP)
