Neurotransmitters, receptors and signalling — viva · Psych Vivas

Prompt

Examiner draws a blank synapse on the whiteboard and says: 'Fill in transmitters, receptors, second messengers, then hang six drug classes and two toxidromes on your diagram.'

Station structure

Time: 8–10 minutes. Depth: consultant teaching registrar. Expect clean definitions, pathway tables, and safe toxidrome discrimination without undergraduate slogans.[1][3]

Core questions and model points

Ionotropic vs metabotropic. Ionotropic = ligand-gated ion channel (GABA-A, NMDA, 5-HT3, nicotinic). Metabotropic = GPCR with second messengers (most monoamine receptors, muscarinic, GABA-B, mGluR).[2][5]
Four dopamine pathways. Mesolimbic efficacy; mesocortical secondary negatives risk; nigrostriatal EPS; tuberoinfundibular prolactin. Version III: striatal dysregulation as final common pathway.[1]
5-HT clinical map. Name 1A, 2A, 2C, 3 with hooks (anxiolytic cascade teaching; SGA/psychedelic; metabolic/appetite; nausea).[2]
Why SSRIs take weeks. Initiation (SERT block) vs adaptation (receptors, cascades, circuits) — Hyman–Nestler.[3]
BZD mechanism. GABA-A PAM, not direct agonist; dependence/withdrawal as chronic PAM exposure problem.[6]
Glutamate exam hooks. NMDA hypofunction/PCP model of psychosis; ketamine rapid antidepressant cascade language.[5]
Toxidromes. Serotonin toxicity (Hunter, clonus) vs NMS (dopamine hypofunction, rigidity).[4]

Pass criteria

Accurate ionotropic/metabotropic distinction.[2]
Pathway–side-effect dopamine map correct.[1]
Delayed AD onset explained as adaptation, not “levels rising slowly.”[3]
Serotonin toxicity vs NMS not confused.[4]
At least one non-monoamine system (GABA or glutamate or ACh) used correctly in a clinical example.[5][6]

References

[1]Howes OD, Kapur S The dopamine hypothesis of schizophrenia: version III--the final common pathway Schizophr Bull, 2009.PMID 19325164
[2]Barnes NM, Sharp T A review of central 5-HT receptors and their function Neuropharmacology, 1999.PMID 10462127
[3]Hyman SE, Nestler EJ Initiation and adaptation: a paradigm for understanding psychotropic drug action Am J Psychiatry, 1996.PMID 8561194
[4]Dunkley EJ, Isbister GK, Sibbritt D, et al. The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity QJM, 2003.PMID 12925718
[5]Javitt DC, Zukin SR Recent advances in the phencyclidine model of schizophrenia Am J Psychiatry, 1991.PMID 1654746
[6]Soyka M Treatment of Benzodiazepine Dependence N Engl J Med, 2017.PMID 28328330

Core questions and model points

Ionotropic vs metabotropic. Ionotropic = ligand-gated ion channel (GABA-A, NMDA, 5-HT3, nicotinic). Metabotropic = GPCR with second messengers (most monoamine receptors, muscarinic, GABA-B, mGluR).[2][5]

Four dopamine pathways. Mesolimbic efficacy; mesocortical secondary negatives risk; nigrostriatal EPS; tuberoinfundibular prolactin. Version III: striatal dysregulation as final common pathway.[1]

5-HT clinical map. Name 1A, 2A, 2C, 3 with hooks (anxiolytic cascade teaching; SGA/psychedelic; metabolic/appetite; nausea).[2]

Why SSRIs take weeks. Initiation (SERT block) vs adaptation (receptors, cascades, circuits) — Hyman–Nestler.[3]

BZD mechanism. GABA-A PAM, not direct agonist; dependence/withdrawal as chronic PAM exposure problem.[6]

Glutamate exam hooks. NMDA hypofunction/PCP model of psychosis; ketamine rapid antidepressant cascade language.[5]

Toxidromes. Serotonin toxicity (Hunter, clonus) vs NMS (dopamine hypofunction, rigidity).[4]

Pass criteria

Accurate ionotropic/metabotropic distinction.[2]

Pathway–side-effect dopamine map correct.[1]

Delayed AD onset explained as adaptation, not “levels rising slowly.”[3]

Serotonin toxicity vs NMS not confused.[4]

At least one non-monoamine system (GABA or glutamate or ACh) used correctly in a clinical example.[5][6]

References

[1]Howes OD, Kapur S The dopamine hypothesis of schizophrenia: version III--the final common pathway Schizophr Bull, 2009.PMID 19325164
[2]Barnes NM, Sharp T A review of central 5-HT receptors and their function Neuropharmacology, 1999.PMID 10462127
[3]Hyman SE, Nestler EJ Initiation and adaptation: a paradigm for understanding psychotropic drug action Am J Psychiatry, 1996.PMID 8561194
[4]Dunkley EJ, Isbister GK, Sibbritt D, et al. The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity QJM, 2003.PMID 12925718
[5]Javitt DC, Zukin SR Recent advances in the phencyclidine model of schizophrenia Am J Psychiatry, 1991.PMID 1654746
[6]Soyka M Treatment of Benzodiazepine Dependence N Engl J Med, 2017.PMID 28328330