they are newer foci of research in understanding the biological basis of psychiatric disorders. It includes CRH,TRH, urocortins,oxytocin, vasopressin.

1. NEUROPEPTIDES – THEIR ROLE IN
PSYCHIATRY
Dr.V.MURUGAVEL
FINAL YR DNB RESIDENT

3. WHAT IS A NEUROPEPTIDE ?

4.  Synaptic communication was long thought to be
mediated solely by classical neurotransmitters such
as monoamines, amino acids and acetylcholine. In
the last decade, however, an increasing number of
peptides have been found in CNS neurons.

5. DAVID DE WIED COINED THE TERM IN 1969

6.  Neuro-peptides can be defined as those
peptides who affect communication between
neurons either by direct transmitter action or
indirectly via neuro-modulation
 More than 100 active neuro-peptides in brain

8. CLASSIFICATION
they can be classified into the categories:
1. Opioid neuropeptides (met-enkepalin,leu-
enkephalin,-endorphin, dynorphin),
2. Gut-brain peptides (substance P, cholecystokinin,
galanin, bombesin,neurotensin, neuropeptide Y),
3. Hypothalamic releasing hormones (corticotropin-
releasing factor, hypocretin, melanin-concentrating
hormone (MCH)),
4. Pituitary hormones (AVP, ACTH),
5. Miscellaneous peptides (bradykinin).

9. CLASSIFICATION(CONTD..)
 Also as
1. Sleep related
2. Stress related
3. Appetite related

10. SYNTHESIS

11. DEGRADATION

13. WE STUDY
1. Cortico tropin releasing factor CRF
2. Urocortins
3. Thyrotropin releasing hormone
4. Oxytocin
5. Vasopressin
6. Neurotensin
7. Neuropeptide Y, substance P,
Cholecystokinin

14. CRF
 HPA axis
 PVN (paraventricular) of hypothalamus.
 Stress-CRH-ACTH- Cortico-steroids
 Animal experiments
 Increased responsiveness, loco-motor
activity
 Decreased exploratory behaviour

15.  Hyperactivity of HPA in Depression
 Due to altered sensitivity of pituitary to GC
negative feedback
 Due to pituitary CRF receptor down
regulation.
 Drug targets CRF1 antagonists

16. UROCORTINS
 Urc 1- EW nucleus,lateral olivary,supraoptic
 Urc 2-hypothalamus
 Urc 3- amygdala, perifornical area, preoptic
area
 Urc 2,3
 ANXIOLYTIC
 Dampens stress response
 ?? CRF and Urc antagonistic

20. OXYTOCIN & VASOPRESSIN
 Posterior pituitary
 Magnocellular neurons of PVN
 Peripheral
 Oxy- uterine contraction,milk ejection reflex
 AVP-anti diuretic hormone
 V1a,V1b-BRAIN
 V2-KIDNEY receptors

21. OXYTOCIN & VASOPRESSIN
Social cognition
Promotes pro social behaviour

25. NEUROTENSIN
 Mesolimbic dopamine system
1. NT system anatomy
2. Antipsychotics modulating NT functions
3. Alterations in schizophrenia patients in CSF,
receptor densities in ento-rhinal cortex

26. NEUROTENSIN
 Research
 High dopamine regions , high NT
concentrations
 Hypothesized that NT is an endogenous
antipsychotic

27. TRH

29. OTHER NEUROPEPTIDES
 CCK
 GI tract,brain
 Emotion and sensory processing
 Panic disorder
 Penta gastrin, a synthetic agonist
 Raises BP, pulse, HPA activation and
physical symptoms

30.  Substance P
 Pain neuro transmitter
 Amygdala,hypothalamus,PAG,LC,para
brachial nucleus
 Major depression, PTSD

31.  Neuropeptide Y
 Regulates appetite,reward,anxiety,energy
balance
 Depression,suicide reduced NYP levels
 High NYP response to stress- resilience-
reduced vulnerability to have mental illness

32. QUESTION:
 Can oxytocin make a Anti social personality
become social?