Regulation of Neurotransmitter

1. Types

   Nota:

   • Biogenic Amines comes in several flavours: One is Catecholamines:  It consists of Dopamine Noradrenaline and adrenaline Serotonin and histamine also acts as a neurotransmitter.
   1. Cathecholamines
      1. Synthesis of Catecholamines

         Nota:

         • Tyrosine was hydrolysed by tyroxine hydroxyls into Dihydroxyphenylalanine (L-Dopa) L-Dopa was then decarboxylated by L-Aromatic amino acid decarboxylase to dopamine Dopamine was then hydroxylase by dopamine beta-hydroxylase into Noradrenaline Noradrenaline was they processed by phenylethanolamine -N-Methyltransferase (PNMT) to Adrenaline.
      2. Metabolism
   2. Serotonin

      Nota:

      • Also known as 5HT
      1. Synthesis

         Nota:

         • Tryptophan is hydrolysed using tryptophan hydroxylase to 5-hydroxytryptophan. 5-hydroxytryptophan is then decarboxylased via L-Aromatic amino acid decarboxylase  into 5HT
      2. Metabolism

         Nota:

         • Metabolism is done by MAO (monoamine oxidase and aldehyde dehydrogenase into 5-hydroxyindoleacetic acid (5HIAA)
2. Roles

Nota:

• 1. Action Potential 2. Calcium Channel opens 3. Release of Neurotransmitters 4. Activation of Receptors 5. Postsynaptic cell signalling 6. Degradation of neurotransmitter 7. Reuptake

1. Sympathomimetic Amines

   Nota:

   • Taken up by the vesicles and it leads to an increased release of noradrenaline from nerve terminals hence leading to increased activation of adrenergic receptors.
   1. Ampthetamine

      Nota:

      • Amphetamine caused intake to the VMAT and initiate reversed transport
2. Uptake1/ Noradrenaline Transporter

   Nota:

   • Desipramine and cocaine Desipramine, blocked the uptake of noradrenaline into the nerve terminal, increasing the duration of action of prior released noradrenaline.
3. Monoamine oxidase Inhibitors

   Nota:

   • Decreased metabolism of noradrenaline, block the enzyme that degrades noradrenaline. Cheese effect: I.e effect created by cheese, Inhibitor to degrade MAO
4. Serotonin

   Nota:

   • Could affect AP, synthesis of transmitter, storage, metabolism, release, reuptake, degradation, Receptors
   1. MDMA

      Nota:

      • Ecstasy or 3,4 methylenedioxymethamphetamine Is a substrate for SERT and increase levels of serotonin, can also act directly as an agonist at 5HT2/1b receptors.
   2. Selective Serotonin Reuptake Inhibitors

      Nota:

      • SSRI: I.e Fluoxetine: Block the uptake of serotonin into the nerve terminal, increased duration of action of released serotonin