Receptors and its classificationvpp
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There are four main types of receptors: channel-linked (ionotropic) receptors, G protein-linked (metabotropic) receptors, enzyme-linked receptors, and intracellular receptors. Channel-linked receptors have the fastest onset of action, in milliseconds, and include nicotinic cholinergic and NMDA receptors. G protein-linked receptors signal through second messenger systems and have an onset of seconds, such as adrenergic receptors. Enzyme-linked receptors signal through kinase pathways and have an onset of minutes, such as insulin receptors. Intracellular receptors include steroid receptors and regulate gene transcription with effects over days.
Receptors and its classificationvpp
- 1. RECEPTOR TYPES CHANNEL LINKED (IONOTROPIC) G PROTEIN LINKED (METABOTROPIC) ENZYME LINKED INTRACELLULAR RECEPTOR (RECEPTORS REGULATING GENE TRANSCRIPTION /NUCLEAR RECEPTORS)
- 3. CHANNEL LINKED (IONOTROPIC) : The cell surface has a selective ion channel like Na, K , Ca , or Cl . Onset of action through these types of receptors is fastest – milliseconds. Nicotinic cholinergic receptors, GABA-A and NMDA receptors. Cl-influx Hyperpolarisation of neuronal membrane(> -90mv) -70 mv Antianxiety, General anaesthesia, Anticonvulsant effects
- 4. G PROTEIN LINKED (METABOTROPIC) : These are cell membrane receptors which are linked to effector mechanisms through G-proteins. Effector mechanisms includes adenylyl cyclase, phospholipase C Onset of response in seconds. Eg : adrenergic receptors, histamine receptors
- 5. MECHANISMS: Through IP3-DAG pathway G-Protein receptors
- 7. ENZYME LINKED(Kinase linked) These cell membrane receptors are enzymatic in nature Insulin acts through this receptors. Onset of response in minutes.
- 8. INTRACELLULAR RECEPTOR These includes Steroids, Thyroxine and Vit–D It takes days to produce its actions (RECEPTORS REGULATING GENE TRANSCRIPTION/NUCLEAR RECEPTORS)
- 9. Classification of ion channels Gating mechanism Leakage channels Voltage –gated channels Ligand –gated channels Ions transported Ca2+ ion channels Na+ ion channels Cl- ion channels K+ ion channels
- 10. Inhibitory function. Nicotinic cholinergic GABA-A Glycine Excitatory function NMDA kainate
- 11. G-PROTEIN COUPLED RECEPTORS:- 1. Adrenergic receptors 2. Cholinergic receptors 3. Seretonergic receptors 4. Dopaminergic receptors 5. Histaminergic receptors 6. GABA/BZ-receptors 7. Excitatory amino acid receptors 8. Opioid receptors 9. Purinergic receptors
- 12. 1)ADRENERGIC RECEPTORS I α & β-ADRENERGIC RECEPTORS α -ADRENERGIC RECEPTORS a) α -1RECEPTORS b) α -2 RECEPTORS 2 β RECEPTORS a) β -1RECEPTORS b) β -2 RECEPTORS c) β -3 RECEPTORS
- 13. 2)CHOLINERGIC RECEPTORS THERE ARE 2 TYPES OF RECEPTORS MUSCARINIC RECEPTORS a)M-1 b)M-2 c)M-3 NICOTINIC RECEPTORS a)NM b)NN c)NN1 d)NN2
- 14. 3) SERETONERGIC (5-HT) RECEPTORS 1) 5-HT-1 2)5 HT-2 3)5 HT-3 4)5 HT-4
- 15. 4) DOPAMINERGIC RECEPTORS THERE ARE 2 CLASSES 1)D1-Receptors 2)D2-Receptors
- 16. 5) HISTAMINERGIC RECEPTORS There are 2 types 1)H1-Receptors 2)H2- Receptors
- 17. 6) GABA RECEPTORS Three different types of GABA-Receptors are:- 1)GABAA 2)GABAB 3)GABAC
- 18. 7)EXCITATORY AMINO ACID RECETORS :- These are of 4 types:- 1)NMDA 2)AMPA 3)Kainate 4)Metabotropic
- 19. 8) OPIOID RECEPTORS There are 3 types in this are:- 1)µ-Opioid Receptors 2)κ-Opioid Receptors 3)δ-Opioid Receptors
- 20. 9)PURINERGIC RECEPTORS There are 2 types in this are:- 1)p1(adenosin receptors) 2)p2(adenosin triphoshate/ATP receptors)