Download MBBS Physiology Presentations 26 Nerve Muscle Physiology Neurotransmitters Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Physiology 26 Nerve Muscle Physiology Neurotransmitters PPT-Powerpoint Presentations and lecture notes

NEUROTRANSMITTERS

Properties

. Neurotransmitters must be synthesized in

the neuron

. Should be stored in presynaptic endings
. Should be released at the synapse
. Should have specific receptors
. Should be disposed off by a specific

mechanism
Classification

. Acetylecholine
. Amines ? NE, Epinephrine, DA, Serotonin,

Histamine

. Amino Acids-
Excitatory: Glutamate, Aspartate
Inhibitory: Glycine, GABA
. Polypeptides ? ADH, Subs P, NPY,

Endorphins, Enkephalins, SST

. Purines- AT P, Adenosine
. Gases ? NO, CO


Histamine

. Histaminergic neurons found in:
. Post hypothalamus
. Gastric mucosa
. Mast cells
. Receptors- H1, H2, H3
. Arousal, sexual behavior, blood pressure,

drinking, pain thresholds, regulation of ant.

Pit hormones

ATP-
. Mediates synaptic response in autonomic

nervous system and habenula

. Receptor- P2X, P2Y, P2U

Substance P-
. Found in intestine, peripheral nerves, CNS
. Neurokinins- NK1, NK2, NK3
. Responsible for pain, on injection causes

redness and swelling, peristalsis, axon reflex
Opioid Peptides

. 2 types of ligands ? met-enkephalin

- leu-enkephalin

. Brain and GIT contains receptors for

opioid.

. Enkephalins are also found in substantia

gelatinosa

. Endogenous opiod peptides are secreted

as precursor molecules

- 3 opioid receptors- ?, ,
- All are metabotropic receptors

Somatostatin ?
. Effects sensory input
. Locomotor activity
. Cognitive functions
. 5 receptors- SSTR1-SSTR5
. Neuropeptide Y-
- Present in brain and autonomic nervous

system

- Receptors ? Y1 ? Y8
- Acts to increase food intake, vasoconstriction

. Nitric oxide (NO)-
-Released by endothelium of blood vessels
- Also found in brain
- Synthesized on demand

. Cannbinoids-
- Rapidly synthesized after Calcium influx after

a neuron is depolarized

- Induces euphoria
- Has anti-nociceptive effect
- Ex- Anandamide and 2-arachidonyl glycerol