An ICD may describe: 1  The inputs and outputs of a single system, e.g.  2 The Wikipedia Interface Control Document.. 3  The interface between two systems or subsystems, e.g.  4 The Doghouse to Outhouse Interface Control Document..n application programming interface is a form of ICD for a software system, in that it describes how to access the functions and services provided by a system via an interface. If a system producer wants others to be able to use the system, an ICD (or equivalent) is a worthwhile investment.
Lesson Summary. Norepinephrine is a neurotransmitter secreted by neurons in the sympathetic nervous system. This chemical is secreted in response to stress, which triggers the 'fight or flight response.' The release of norepinephrine causes several changes that help our body to work more efficiently.esson Summary. Norepinephrine is a neurotransmitter secreted by neurons in the sympathetic nervous system. This chemical is secreted in response to stress, which triggers the 'fight or flight response.' The release of norepinephrine causes several changes that help our body to work more efficiently.
SNRIs are also sometimes used to treat other conditions such as anxiety and nerve pain. Serotonin (ser-o-TOE-nin) and norepinephrine (nor-ep-ih-NEF-rin) reuptake inhibitors ease depression by affecting chemical messengers (neurotransmitters) used to communicate between brain cells.Like most antidepressants, SNRIs work by changing the levels of one or more of these naturally occurring brain chemicals.SNRIs block the absorption (reuptake) of the neurotransmitters serotonin and norepinephrine in the brain. They also affect certain other neurotransmitters.ike most antidepressants, SNRIs work by changing the levels of one or more of these naturally occurring brain chemicals. SNRIs block the absorption (reuptake) of the neurotransmitters serotonin and norepinephrine in the brain. They also affect certain other neurotransmitters.