Pain is defined as an uncomfortable feeling that signals something wrong is occurring. the pain can be described as being steady, throbbing, stabbing or pinching. pain is caused due to links with tissue damage.

we have 3 types of pain namely:

1) Nociceptive inflammatory pain

2) Nociceptive pain

3) Neuropathic pain

pain occurs when our skin sends message via nerve fibres called the A-delta and C fibres, to the spinal cord and the brainstem and then into the brain where the pain sensation is activated.

1. membrane potential and Action potential

2. voltage-gated 

i) responds to changes in membrane potential of the cell

ii) transmits signal from cell body to nerve terminal

iii) Na, K and Ca ion channels

ligand-gated channels

i) binding of ligand (NT) to ion channel.

ii) Are responsible for fast synaptic transmission typical of hierarchical pathways in CNS.

iii) are ionotropic receptors

3. ionotropic receptors consists of multiple subunits and binding of the neurotransmitter ligand directly opens the channels whereas metabotropic receptors has 7 transmembrane G protein-coupled receptors and consists of the binding of NT to this type of receptor that does not result in direct gating of a channel.

4. transduction systems rely on the formation of 2nd messenger:

Metabotropic receptors;  Adenyl cyclase system and phospholipase C system. they are basically G protein coupled receptor proteins.

ionotropic receptors; GABAa, nicotinic EAA and 5-HT3

5. EPSP is whereby it receives an excitatory presynaptic cell, connected to the dendrite, which fires an action potential.

IPSP is a temporary hyperpolarization of postsynaptic membrane caused by the flow of negatively charged ions into the postsynaptic cell.

6. the Ca ions role is to direct structural as well as functional adaptations in the individual neurons that leads to the establishment of the synaptic specificity.