CAL Flashcards
What types of receptors are dopamine receptors?
GPCR
What do D1 receptors do?
D1 and D5 subtypes
- post-synaptic activate adenylate cyclase
What do D2 receptors do?
D2,3,4 subtypes
- inhibit adenylate cyclase
- activate K+ channels
- reduce calcium conductance
- potentiate ATP-mediated arachidonic acid release
Which dopamine receptor subtypes are found in the limbic system?
D1, D5, D2, D3
Which pathways involved dopamine?
- nigrostriatal
- mesolimbic
- mesocortical
- tuberoinfundibular
What is the route of the mesolimbic system?
Ventral tegmental area of midbrain -> axons project to nucleus accumbens and olfactory tubercle
- hyperactivated in schizophrenia
What is the route of the mesocortical system? What is its function?
Ventral tegmentum of midbrain -> axons project to frontal and cingulate cortex
- hypoactivated in schizophrenia
- responsible for memory, motivation, emotional, reward, desire, addiction
What is the route of the tuberoinfundibular pathway? What is its function?
- links arcuate nucleus of hypothalamus to pituitary
- hormone regulation, maternal behaviour, pregnancy and sensory processes?
What pathways involve serotonin?
5-HT neurone cell bodies in raphe nuclei in the pons
- caudal nuclei in lower brainstem projects to medulla
- rostral nuclei in upper brainstem projects to forebrain
Cell bodies also in locus coeruleus
What types of receptors does serotonin act on?
GPCR
7 families
Except 5-HT3 which are ligand gated ion channels
What do 5-HT1 receptors have in common?
- coupled to adenylate cyclase by G protein
- G protein also directly activates K+ channels reducing neuronal excitability
5-HT1a receptors
Inhibitory somatodendritic autoreceptors
Activate K+ conductance via G protein = post synaptic hyperpolarisation
5-HT1b receptors
Inhibitory autoreceptors and heteroreceptors
Presynpatic
5HT1c receptors
5-HT2c
5HT1d receptors
A and B types
B - cranial vessels, sumatriptan vasoconstricts them counteracting CGRP vasodilation in a migraine
5HTf receptors
Uterus
5-HT2 receptors
Coupled to inositol phosphate
5-HT2a receptors
Frontal Cortex, widespread
tracheal/bronchial SM contraction, platelet aggregation, increases capillary permeability
Anxiety, depression, nociception
5-HT2b receptors
GIT contraction
Gut, heart, kidney, lung, cortex, limbic
5-HT2c receptors
5-HT1c
spinal and supraspinal
Choroid plexus endothelial cells = CSF formation
5-HT3 receptors
Ligand gated Depolarisation, neuronal excitation, inhibition of transmitter release Emetic - area prostrema Amygdala - anxiety Dorsal horn of primary afferents GI tract
5-HT4 receptors
Positively coupled to adenylate cyclase
Reduces K+ and increases Ca2+ conductance = relaxation of oesophageal SM
- indirectly releases Ach contracting GIT SM and increases cardiac force and rate of contraction
5-HT6 receptors
Positively coupled to adenylate cyclase
Antidepressants target
5-HT7 receptors
Positively coupled to adenylate cyclase
Neuroleptics target
