Once dopamine is on the move somatostatin starts to try to shut down the onset of the manic mood. It does this by having the ability of blocking glutamate at the presynaptic transmission terminals. Glutamate being the dominant excitatory neurotransmitter in the CNS. The more dopamine produced the more somatostatin inflicts itself upon glutamate. Somatostatin modulates dopamine indirectly by going through glutamate expression which can be faciliatory or inhibitory. If this mechanism fails to harness rising dopamine levels, mania is on the horizon.

Gaba the major inhibitory transmitter which is the gate keeper of neuromodulators such as noradrenaline and adrenaline becomes also dysfunctional as glutamate is its metabolic precursor. Serotonin is involved in wakefulness; sleep onset and preventing REM sleep. It’s also required to produce melatonin. It’s thought to be a mood stabilizer and possesses the ability to even lift mental wellbeing.

https://www.healthline.com/health/dopamine-vs-serotonin https://nestednaturals.com/blogs/blog/what-is-serotonin-and-how-does-it-affect-your-sleep?msclkid=328ed00fce7011eca9b5895407242ad9

Another casualty to somatostatin is cortisol. Somatostatin blocks ACTH
(adrenocorticotropic Hormone) which controls the production of cortisol.
Cortisol is prominent in stress management and if needed can sustain a positive mood over a short period of time when dopamine is low. It increases the effectiveness of catecholamines like adrenaline which creates the necessary energy while improving mood. Long term it produces a detrimental effect. Somatostatin is also a potent inhibitor of insulin and glucagon which means it can control energy with all these qualities in place. Somatostatin should be able to contain the ever increasing dopamine levels and clock the euphoric activity. If dopamine continues to soar Bipolar 1 sufferers can experience psychosis, and if left untreated they can progress into displaying serious and distressing symptoms
when approaching the inevitable downward cycle. https://medium.com/@EricBravermanMD/dopamine-and-cortisol-6662cd5cac7f

Dopamine functions and its relationship with the pineal gland are responsible for the switch. As dopamine rises to unprecedented levels it blocks acetylcholine which is a neurotransmitter and also the constrictor of the pupil in the eye. Dopamine also competes with noradrenaline by binding to its receptors that dilate the pupil of the eye. This battle is eventually won by dopamine and negligible amounts of noradrenaline are able to engage successfully. This means that natural light will enter the pineal gland in a very unique way and there will be virtually no melatonin produced as noradrenaline influences the synthesis of the hormone.