Adejumo's Assign Slide

8/8/2019 Adejumo's Assign Slide

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NEUROTRANSMITTERSAND BEHAVIOUR

PSY 741- PHYSIOLOGICAL PSYCHOLOGY


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INTRODUCTION

Complex Nature Of Behaviour

Behaviour goes beyond what meets the eye.

What processes underlie all we exhibit?

Physiological Psychology and behaviour:

That arm of psychology that attempts tounderstand the relations between biological

processes (physical and chemical processes)

and behaviour.


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The Nervous System

The Neuron: Basic specialized cell of the

nervous system.


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Typical Layout of neurons in the body


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Movement of impulse to and away from the neuron


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Communication at the synapse


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THE DISCOVERY OF NEUROTRANSMITTERS

T = time

S = stimulus in the vagus

D = contractions of heart D

R = contractions of heart R

Fig. 1: tto Loewis experiment (1921)


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What then are Neurotransmitters?

Tiny liquid

Synthesized by the neuron from materials in

the blood Chemical messengers across the synapse

Bind themselves to receptors across the

synapse Inhibitory or excitatory

The influence behaviour


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Discovery of each Neurotransmitters

Acetylcholine 1930s Adrenaline 1940s

(Noradrenaline a derivative)

Serotonin - 1940s

Dopamine 1950s Substance P late 1950s

Four amino acids discovered in 1960 Glutamate, Aspartate (as excitatory agent), GABAand Glycine (as inhibitory agents)

Neuropeptides -1970s

After these a lot more have been discovered and are still beendiscovered.


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Biosynthesis, packaging, and release of neurotransmitters


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A quick review of synaptic action

receptor types (ionotropic and metabotropic)

receptor subtypes


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Catecholamine synthesis

-this is notfor torture

-understanding

synthesis can beimportant for

understanding drug

action


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Dopamine

Subtantia nigra and

Parkinsons disease

Mesocorticolimbic systemand schizophrenia


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Serotonin synthesis


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Serotonin

Serotonergic pathways in the brain

-ra he, 15 subt es, Prozac and de ression


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Acetylcholine synthesis


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Amino acids: The workhorses of

the neurotransmitter familyGlutamate - the primary excitatory neurotransmitter

in brains

GABA (Gamma-amino-butyric-acid) - the primary

inhibitory

neurotransmitter


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The fabulous glutamate receptor

Activation of NMDA receptor can cause changes in the

numbers ofAMPA receptors a mechanism for learning?


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The fabulous GABA receptor

Multiple binding sites


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Peptides

Produced in minute quantities

often substances that are also found in areas of body

other than brain (vasoactive intestinal polypeptide)

tremendously potent and long-acting

(neuromodulatory)

opiates


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Characteristics of ajor eurotransmitters

Neurotransmitter Location Functions

Acetylcholine (Ach) Neuromuscular junctionPreganglionic autonomic

synapses

Postganglionicparasympathetic synapsesBasal forebrain projections

to hippocampus andamygdala.

MovementAutonomic function

Learning and memory

Dopamine Substantia nigra and basal

gangliaVentral tegmentumprojections to hippocampus

and amygdala, and nucleusaccumbens

MovementReinforcementPlanning


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Norepinephrine(Noradrenalin)

Pons (especially Locuscoeruleus, which projects

widely to spinal cord andbrain)

MedullaHypothalamus

Postganglionic sympathetic

Arousal and vigilanceMood

Serotonin Projections originate in thepons, particularly the raaphe

nucleus, and project widely inthe brain and spinal cord

SleepAppetite

Mood

Glutamate Widely distributed in the central

nervous system

Excitation

Long- term memory

GABA Widely distributed in the centralnervous system

InhibitionMood

Seizure threshold


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Adenosine triphosphate(ATP)

Central nervous systemneuromodulator

Autonomic nervoussystem

Frequently found inaxons containing

catecholamines

Pain modulation

Endogenous Opioids Periaqueductal grayHypothalamus

Pituitary glandLimbic system

Basal gangliaSpinal cord

Ventral tegmentum

Pain reductionFeelings of well-being

Substance P Spinal cord Pain

Nitric Oxide (NO) Central and peripheralnervous systems

Smooth muscle

Relaxes smooth musclecell in blood vessels

ErectionPossible retrograde

signaling


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NEUROTRANSMITTERS AND DRUGS

What is a drug? A very vague term

all ingested substances alter bodilyfunction

drug is reserved for things that havepronounced effects when ingested in smallquantities

NT agonists drugs that increase NT effects

NT antagonists - drugs that decrease

NT effects


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Ways that drugs can antagonize

Block release

Receptor blocker

Prevent synthesis


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SUMMARY OF SOME DRUGS AND THEIR

EFFECTSDrugs Main effects on behaviour Main effect on Synapses

Amphetamine Excitement, alertness,elevated Mood, decreased

fatigue

Increases release ofdopamine and several

other neurotransmitters

Cocaine Excitement,Alertness,elevated mood , decreased

fatigue

Blocks reuptake of

Dopamine and several other

Neurotransmitters

Methylphenidate Increased concentration Blocks reuptake of

Dopamine and others butmore gradually thanCocaine does.

Nicotine Mostly stimulant effects Stimulate Nicotinic typeacetylcholine, receptor

Opiate Relaxation, withdrawal,decreased painS

timulate endorphinreceptors


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Cannabinoids(marijuana)

Intensified sensoryexperiences, distorted

sense of time,decreased pain and

nausea

Excite negative feetback, receptors on

presynaptic cells,thereby put the brakes

on release of eitherglutamate or GABA

LSD Distorted sensations Stimulate serotonin typetwo receptors (5-HT2)

Alcohol Relaxation, decreasedattention

Felicitates GABA,receptor


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Neurotransmitters and Psychological

Disorders Alzheimers disease : Not-enough

acetylcholine activity in the brain

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