2. CALCIUM CHANNELS
• 4 types of ca2+ channels have been identified in the body.
1.L-Type
2.N-Type
3.P-Type
4.T-Type
• Calcium channels are present in many tissues which are
relevant to the nervous tissue where the entry of ca2+into nerve
terminals plays a key role in cardiac, muscular and neuronal
functions.
• Calcium channels regulate the intracellular concentration of
calcium ions.
3. L-Type:
Location –Cardiac & smooth muscle,SA node,AV node.
Function – Regulate excitation -contraction coupling pacemaker
activity &conduction velocity.
N-Type:
Location &Function – Located in synaptic terminals,function in the
nervous system,heart & kidneys.They are important in
neurotransmitter release.
4. P-Type:
Location – Axon terminals,Neurons of CNS & PNS
Function – Neurotransmitter and hormone release at synaptic terminals
of excitatory and inhibitory synapses.
T-Type –
Location – Brain,PNS,Heart,Smooth muscle,Bone and endocrine system.
Function – To control the pacemaking activity of the SA Node within the
heart and action potentials within the thalamus
5. CALCIUM CHANNEL BLOCKERS
• Drugs which block the calcium channels and are used in the
treatment of various cardiovascular diseases are called calcium
channel blockers.
CLASSIFICATION
1.Phenylalkylamines – Verapamil,Bepridil Hcl
2.1,4-Dihydropyridines – Nifedipine,Amlodipine,
Nimodipine,Felodipine,Nicardipine
3.Benzothiazepines – Diltiazem Hcl
10. USES OF CALCIUM CHANNEL BLOCKERS
To treat angina pectoris
To treat supra ventricular arrythmias
To treat Hypertension
To treat Mygraine
To treat Raynaud’s Phenomenon