Week 7 Flashcards
What 5 examples of Pain syndromes?
- Bone (worse on weight bearing)
- Nerve (burning/shooting/tingling)
- Liver (upper right quadrant)
- RIP (headache and/or nausea)
- Colic (cramping pain)
What are the 3 steps in managing chronic pain according to WHO
AND
what drugs may be used for each?
Step 1 - Non-opioid
(aspirin, paracetamol or NSAID)
Step 2 - Weak opioid
(codeine +/- non-opioid)
Step 3 - Strong opioid
(morphine +/- non-opioid)
+/- Adjuvant for all steps
What are the Indications, Actions, and Cautions of Morphine?
Indications
Moderate to severe pain / dyspnoea (breathlessness)
Action
Opioid receptor agonist (u-receptors). Centrally acting
Cautions
Longlist in BNF; including renal impairment and elderly; Avoid in acute respiratory depression
By what methods may Opioids be administered?
Oral / Rectal
Parenterally - im/sc injections
Delivery via syringe driver over 24h
What should you do when starting Strong opioids (step 3)?
- Stop any ‘Step 2’ weak opioids
- Titrate immediate release strong opioid
- Convert to modified release form
- Monitor response and side-effects
What are the 2 types of Opioid release in BNF?
Modified (slow) release
and
Immediate release
What are 3 examples of Modified release in opioids
AND
what are some examples of drugs used for these?
- ‘Background’ pain relief
- Twice daily prep at 12h intervals (Filnarine)
- Once daily prep at 24h intervals (MXL)
When are Imediate release opioids used
AND
what are some drug examples?
- ‘Breakthrough’ pain
- As required (PRN)
Oramorph liquid / Sevredol tabs
What is Diamorphine and what are some differences between in and Morphine?
Heroin
- Semi-synthetic morphine derivative
- More soluble than Morphine -> smaller vol needed
- Can be used for parenteral administration (injection / syringe driver)
What are some OTHER opioids than just Morphine?
Oxycodone
- second line opioid
- less hallucinations, itch, drowsiness, confusion
Fentanyl patch
- second line opioid
- lasts 72h
- only use in stable pain
- useful if oral and sc routes not available
- useful if persistent side-effects w/ morphine / diamorphine
What are some side effects of opioids?
- N&V
- Constipation
- Dry mouth
- Billary spasm
How do you manage Constipation as a result of opioid side-effects?
- Stimulant & softening laxative
- Senna / Bisacodyl + Docusate
- Magrogol e.g. laxido / movicol
- Or Co-Danthramer alone
How do you manage Nausea as a result of opioid side-effects?
- Antiemetic
- Metoclopramide
- Haloperidone (QT interval)
What are some signs of Opioid Toxicity?
- Pin point pupils
- Shadows edge of visual feild
- Increasing drowsiness
- Vivid dreams / Hallucinations
- Muscle twitching / Myoclonus
- Confusion
- Rarely, resp depression
What issues would require Adjunct Medication and what drus would be used for such?
Liver capsule pain / RIP
- Steroids (e.g. Dexamethasone)
- Remember to consider gastroprotection
Neuropathic pain
- Amitriptyline / Gabapentin / Carbamazepine
Bowel / Bladder spasm
- Buscopan (hyoscine butylbromide)
Bone Pain / Soft tissue infiltration
- NSAIDs / Radiotherapy for bony metastases
What are the functions of Syringe Drivers?
- Delivery over 24h - usually sc
- Useful when oral route inappropriate
- Often useful for rapid symptom control
- Multiple medications can be added
- Stigma of being on a ‘pump’
What is the deffinition of Psycho-spiritual distress?
The impaired ability to experience and integrate meaning and purpose in life through connections with self, others, nature, or a higher power
Why is Psycho-spiritual distress important?
May magnify the intensity of physical symptoms
When may Psycho-spiritual distress occur?
- at Diagnosis
- at Home after treatment
- upon Disease progression
- at Terminal phase
How do you manage Psycho-spiritual distress?
- Encourage hope, purpose and meaning
- Respect religious / cultural needs
- Affirming patients humanity
- Protecting patient’s dignity, self worth and identity
What percentage of greif is Non-complex compared to Complex / unresolved?
90-94%
to
6-10%
What may an individual dealing with greif WANT from the NHS?
Medication
(Antidepressants / Benzodiazepines)
Sick line
Counselling
What may an individual dealing with greif NEED from the NHS?
Support and space to be heard
What are the Peripheral aspects of pain?
- Nociceptive receptors
- Nociceptive activation
- Nociceptive fibres
- Sensitisation of receptors
Describe Nociceptive nerves
They have free unspecialised nerve endings with ‘pain’ channels inserted in the membrane
What is the most common Nociceptor nerve?
Transient Receptor Potential family of channels (TRP)
What are Nociceptor nerves sensitive to?
- O2
- pH osmolarity
- Valinoids (spice)
- Heat
What can Nociceptive receptors be sensitised by?
- Substance P
- Bradykinins
- Serotonin
- pH
- ATP
- NO
What is the Composition of the Nociceptive receptors
AND
What does this Allow?
Composed of a 6 unit trans-membrane portion and a ‘basket’ of regulatory complex in the cytoplasm
Allows Ca2+ & Na+ into the cell
What physical stimuli will Activate Nociceptive receptors?
Temperature
- Extreme heat and extreme cold open ‘Transient receptor potential vanilloid’ (TRPV) channels inserted in the membrane
- Allows Na2+ & Ca2+ entry and so depolarises cell to give action potential
Mechanical
- Actual mechanism still unknown. Presumed to be a form of insensitive mechanoreceptor which allows Na entry when activated
Chemical
- Apart from TRPV receptors, it’s largely unknown but chemical transmission can cause sensitisation of pain receptors
What specifically does each molecule do to sensitize nociceptors?
Calcitonin gene regulated peptide (CGRP) and Substance P (SP)
- Recruit silent receptors which increase summation in dorsal horn
Histamine
- Causes hyperalgesia (more pain than normal) through its effects on nerve endings
Bradykinin
- Activates pain fibres directly and causes increase in protaglandins
Tissue damage
- Produces H ions which give muscle ache (weight lifting)
Protaglandin E2
- Aspirin and other NSAIDs act to inhibit this enzyme
What are the two main types of Nociceptive fibres?
Aδ fibres
- Myelinated
- Sharp 1st pain
- Mechanical pinching
- Extreme hot or cold
C fibres
- Unmyelinated
- Aching 2nd pain (diffuse)
- Mechanical pinching
- Thermal and chemical stimuli (polymodal)
Upon stimulation, what NTs do nociceptive fibres release?
- Glutamate
- Substance P
- CGRP (Calcitonin gene-related peptide)
What are some signs of nociceptor activation?
Substance P and CGRP release is responsible for 3 signs:
- Calor (heat)
- Rubor (redness)
- Tumor (swelling)
1 & 2 caused by local hyperaemia (increased blood flow) and 3 is by plasma extravasation (leaking out of veins)
What are the differences between the Paleo-spinothalamic and Neo-spinothalamic pathways?
Paleo-spinothalamic
- Synapses at Dorsal Medial intralaminar portion of thalamus
- Undiscriminating system
- Finally synapses at Limbic system association cortices
Neo-spinothalamic
- Synapses at Vental-posterolateral portion of thalamus
- Discriminating system
- Finally synapses at Primary somatosensory cortex
Where do Nociceptive fibres first synapse in the spinal cord?
Ipsilateral Dorsal Horn
What are the two types of ascending axons for nociceptive fibres?
Nociceptive specific
- C and Aδ only
Wide dynamic range neurons (WDR)
- Any sensory input including pain, can fire in a graded fashion based on C fibre frequency of input (higher pain = higher input)
How do AMPA receptors interact with NMDA receptors?
NMDA recpectors are normaly closed due to Mg2+ Block.
AMPA receptors (once stimulated by Glutamate) allow Ca2+ into the cell which then depolarises.
This releases the Mg2+ block, activating NMDA receptors
What is Central sensitisation - Wind up?
Long term sensitisation of post synaptic neurons in the dorsal horn
Mediated by WDR neurons which, when firing at high frequency, open NMDA channels
The inflow of calcium causes nuclear expression resulting in increased Na channels and a blockade of K channels
The net result is a resting potential closer to threshold and a more sensitive cell
This effectively amplifies the pain signal
What are the three main goals of dorsal horn Wind up?
Priority salience
- You’ll notice it more than normal
Protection
- Prevent futher injury
Memory
- Increased duration of stimuli increases the chance of consolidation
Describe the Gate theory of pain management
C fibres both stimulate the WDR neuron AND inhibit the inhibitory neuron from Aβ fibres that would normal inhibit the WDR. This increase the pain signal
By rubbing the area around the source of pain, you activate a stronger signal in the Aβ inhibitory neuron, therefore decreasing the activation of WDR neuron.
Describe Descending analgesia in the contex of pain management
Periaqueductal gray matter creates inhibition of incoming pain signals at the cord level, aswell as the presence of encephalin-secreting neurons that supress pain signals in the cord
Describe the Endogenous opioid system
These are a group of NTs called:
- Endorphins
- Encephalins
- Dynorphins
Work at opiate receptors and are present at all levels of the pain pathways, therefore doses of opiates can act simultaneously at all levels of the pain pathway providing high efficacy
What would electrical stimulation of the PAG result in?
A strong analgesic effect
(Blocked by Nalaxone)
List some examples of the types of pain
- Chronic / Acute
- Nociceptive / Neuropathic / Phantom limb
- Maladaptive
- Viceral
- Referred
- Sharp / Ache
- Headache
- Complex regional pain syndrome
Describe the characteristics of Nociceptive pain
Results from conditions such as:
- Sprains
- Bone fractures
- Burns, bumps, bruises
- Inflamation
Pain stops when the problem is healed
Responds well to painkillers such as opioids
What are the 3 types of Chronic pain?
- Nociceptive pain
- Neuropathic pain
- Central maladaptation
Describe the characteristics of Neuropathic pain
Pain persists beyond healing process of damaged tissues and may include:
- Hyperalgesia (strong reaction to weak pain signal)
- Allodynia (painful reaction to non painful stimuli like a light touch on sunburn)
- Summation (repeated low innocuous stimuli causing increasing intensity of response)
- Parasthesias (tingling without stimuli)
- Dysthesias (burning / shooting pain without stimuli)
This type of pain is hard to treat and is caused by maladaptation of the dorsal horn wind up and sensitisation systems
What is Central maladaptation?
A type of sensitisation that can lead to long term changes in the structure of synapses in the dorsal horn or the spinal cord
Increases in Ionotropic glutamate receptors (NMDA) cause a sensitivity in second order neurons which then more readily send pain signals to the thalamus
A second component is where descending modulation of the inhibitory interneurons becomes maladapted. This can lead to a reduction in inhibition of WDR neurons and so a dis-inhibition of the second order neurons
List some symptoms of Complex regional pain syndromes
- Severe continuous neuropathic pain
- Abnormal sensation
- Vasomotor change
- Sudomotor change
- Motor / trophic change
- Regionally restricted e.g. hand
- Disproportionate to the trauma
What is the Budapest criteria?
Used to diagnose Complex regional pain syndromes
1) Patients must report continuing pain disproportionate to the trauma
2) Patients must report at least one of the following symptoms:
- Sensory: hyperalgesia
- Vasomotor: skin colour or temp changes
- Sudomotor / oedema: swelling or weating changes
- Motor / trophic: weakness, tremor, dystonia, decreased range of motion or trophic changes
3) Patients must display one sign in two of the above catagories
4) Signs and symptoms must not be better explained by another diagnosis
How does Referred pain work?
Viceral sensory fibres and Skin sensory fibres synapse at the same location in the dorsal horn
In the Gate control theory, what ‘opens’ and ‘closes’ the gate?
Opens
- Inactivity / poor fitness
- Poor pacing
- Anxiety / depression / hopelessness
- Worrying about the pain (cognitive)
Closes
- Appropriate use of medication
- Massage / relaxation
- Heat / cold
- Positive coping strategies
- Exercise
Describe the Biopsychosocial model of pain
Views illness as a dynamic and reciprocal interaction among biological, psychological and sociocultural variables that shape a person’s response to pain
Describe the Cognitive-Behaivoural perspective of pain
emphasizes the important contribution of psychological variables such as
- Do they feel in control?
- What does the pain mean to them?
- The Dysphoric effect
What 3 things are done in a Pain assessment?
- Pain intensity self-report
- Pain intensity by observational scale
- Pain distress
What are the limitations of self-reported pain?
- May be bad at explaining due to verbal skills
- Language barrier
- May downplay or exagerate pain
- Pain may vary in intensity
What are the 4 levels of Chronic pain management?
Level 1 - Self-management
- Combination of activity and relaxation, non opioid painkillers, support from 3rd party organisations
Level 2 - Primary Care
- GP, Physiotherapist or Pharmacist provide help through assessing pain, providing advice, medication, exercise programmes, links to self management, alternative therapies
Level 3 - Secondary Care
- Hospital based pain clinics or services. Multidisciplinary teams, ususally including consultants trained in chronic pain, nurses, physiotherapists, psychologists, pharmacists, occupational therapists and psychiatrists
Level 4 - Tertiary Care
- Highly specialised services
What Frequency can humans hear
AND
at what dB does physical pain occur?
20 - 20,000 Hz
120 - 130 dB
Name the structures
Describe the External acoustic meatus
- 2-3 cm long, Not straight
- Lat. 1/3, Cartilagenous, continuous epithelium with auricular skin
- Med. 2/3, Bony, continuous epithelium with tympanic membrane
- Innervated by CN X (auricular branch) and Auriculotemporal n. (branch of CN V3)
Describe the features of the Tympanic membrane
- Umbo - tip of malleus in contact with membrane
- Cone of light in ant. inf. quadrant
- Innervation from CNs V, VII, X (externally), IX (internally)
Describe the features of the Middle ear cavity
- Mucosa lined cavity w/ mastoid antrum, mastoid air cells and pharyngotympanic tube
- Contains ossicles, muscles (tensor tympani and stapedius), chorda tympani and tympanic plexus
- Innervated by CN IX
Describe the features and functions of the bone in the ear
- Malleus - Incus - Stapes
- Held in place via ligaments
- Transmit sound from tympanic membrane to oval window
- Stapes has annular ligament
- Amplifies force from tymp mem by 22 times
Name and give the functions of the muscles in the Middle ear cavity
Tensor Tympani
- CN V3
- Attaches from pharyngotympanic tube cartilage, petrous temp bone, and greater wing of sphenoid TO handle of malleus
- Tenses tymp mem, reducing amplitude of vibration
- Protects from loud sounds
Stapedius
- CN VII
- 1mm long
- Attaches from inside pyramidal eminence on post wall of tymp cavity TO neck of stapes
- Acoustic reflex - stiffens stapes, pulling away from opal window, reducing transmission
Name and give the routes of the nerves of the Middle ear cavity
Chorda Tympani
- Facial nerve branches within tymp cavity and leaves via pterotympanic fissure to supply tongue
Tympanic Plexus
- Formed from tympanic n. on promontory of tymp cavity, sensory to tymp cavity and gives rise to Lesser petrosal n, ultimately secretomotor to parotid
Descibe the Cochlea
- Vestibulocochlear organ
- Bony and membranous labyrinth within otic capsule
- Ducts within bony canals
- Hearing is concerned with cochlear duct
Name the structures of the Vestibular components and describe their functions
Describe the internal structure of the Cochlea
- Made up of Three co-axial spiral tubes (technically two, one being doubled up)
- Scala Vestibuli - Scala Media - Scala Tympani
- Vestibuli and Tympani are continuous and contain Perilymph
- Media contains Endolymph
- Hair cells in Media are connected to spiral ggl.
How does Sound Transduction work in the cochlea?
- Basilar membrane of Scala Media has physical properties allowing it to resonate at different frequencies along its length
- Low freq travel further (apical end)
- High freq travel less (proximal end)
- When it reaches the part with the same resonance, the sound is “absorbed” causing maximal displacement of basilar membrane
How does movement of Basilar membrane effect hair cells?
Basillar membrane induces shear forces at the tectorial membrane
This causes Cilia in the hair cells to be displaced
If displacement is towards tallest stereocilia, you get depolarisation
What happens at the cellular level in Depolarisation of the Hair cells?
- Mechanically gated K+ channels open, influx of K+ from Endolymph
- Triggers voltage gated Ca channels to open, raises intracellular Ca, causing release of Glutamate
What percentage of auditory nerve fibres serve Inner hair cells and Outer hair cells?
Inner - 95%
Outer - 5%
Describe the function of Prestin in frequency selectivity
- Prestin - motor protein in outer hair cells, allows cells to extend and contract
- Contraction occurs when depolarised
- This causes greater fluid movement around inner hair cells and thus inner hair cells are more sensitive to that frequency
- Allow discrimination of similar frequncies
What is the function of inhibitory input to hair cells from CNs?
- Reduces their response to incoming signals
- “Filters out” less relevant sounds (background noises)
- ACH mediated
- Efferent fibres from olivary nuc. travelling in CN VIII
What is the Central Nerve Pathway for hearing?
- Spiral ggl.
- CN VIII
- Dorsal + Ventral Cochlear nuc. (upper medulla)
- Second order neurones cross
- Sup. Olivary nuc.
- Lat. Lemniscus
- Inf. Colliculus, synapse in midbrain
- Med. Geniculate nuc. in thalamus
- Primary auditory cortex
Describe Tinnitus and what are some of its causes?
Hearing noises that do not come from an external source
- May effect one or both ears
- May sound like buzzing, ringing, hissing
- Linked to hearing loss, diabetes, thyroid disorders, MS, anxiety / depression
- Side effect of some medicines
Name and describe the 2 types of deafness
Conduction - affecting any of the conducting structures
- Blockage
- Ossicle malformation
- Perforated eardrum
- Infection
Sensorineural - affecting any of the peripheral or central nervous structures
- Presbycusis (age related hearing loss)
- Trauma
- Ototoxic drugs
- Stroke
- Noise exposure
Define Ageusia and Dysgeusia
Complete and partial loss of taste
How does Olfactory Epithelium differ from normal respiratory epithelium?
Different Mucous layer and different Cilia function
Describe the Physiology of smell
GPCR binding of odorant to receptor on bipolar cell initiates Adenylyl cyclase to produce cAMP
This acts on nucleotide gated channels allowing Ca2+ and Na+ influx
Ca2+ closes Cl- channels, preventing Cl- efflux
What are the Layers of the Olfactory bulb?
- Olfactory n. layer
- Glomerular layer
- Ext. Plexiform layer
- Mitral cell layer
- Int. Plexiform layer
- Granular layer
OGEMIG
On god egg man is gay
What is the path of nerves for olfaction?
- Unmyelinated Bipolar cells pass through cribriform plate to form glomeruli
- Mitral and tufted cells synapse with these glomeruli
- These form the Olfactory tract which relay to the ipsilateral Primary Olfactory Cortex
What is the function of different brain regions in olfaction?
Orbitofrontal Cortex
- Odour perception and discrimination, integration with taste signals
Amygdala
- Learning, reward system, emotion
Hippocampus
- Learning and episodic memory
What are the 5 taste modalities?
- Sweet
- Salty
- Bitter
- Sour
- Umami
What are the 4 types of taste receptor cells?
Type 1 - support cells
Type 2 - sweet/bitter/umami
Type 3 - salt/sour
Type 4 - progenitor cells
What are the 3 types of taste Papillae?
What is the taste innervation of the different papillae?
Fungiform
- Chorda Tympani (CN VII)
Circumvallate + Foliate
- CN IX
Epiglottis, pharynx, soft palate
- CN X
What is the path of taste nerve signals?
CNs VII, IX, and X carry sensation to nuc. of Solitary tract in brainstem
Synapse in Gustatory nuc (part of solitary tract)
Second order neurones project to ipsilateral VP nuc. of thalamus
Then to primary taste cortex in insula and postcentral gyrus
What are some potential causes of Anosmia?
- Inflammatory/obstructive
- Idiopathic
- Trauma
- COVID-19
- Diabetes
- Medicines
Name all Facia and Compartments in the neck
^^^
Where is the Pretracheal space in relation to other fascia?
Anterior to Pretracheal fascia, posterior to Investing fascia
Where is the ‘True’ Retropharyngeal space in relation to other fascia?
Posterior to Buccopharyngeal fascia, anterior to Prevertebral fascia
Where is the Alar space found?
Within Prevertebral layer of fascia, covers ant. surface of transverse processes & bodies of cervical vertebrae (from base of skull to diaphragm)
What are the borders of the Anterior Triangle in the neck?
What are the borders and contents of the Submandibular and Submental triangles?
Describe the 2 bellies of the Digastric muscle
Ant.- Mylohyoid (CN V3, inf. alveolar)
Post. - Facial n.
Describe Digastric muscle innervation
Describe the borders and contents of the Carotid triangle
Describe the borders and contents of the Omotracheal triangle
List the Supra and Infrahyoid muscles
What is the action and innervation of the Infrahyoid muscles?
Describe the Thyroid gland
What are the lobes of the Thyroid gland?
4 lobes
- 2 Lateral lobes (right & left)
- Midline Isthmus
- Midline Pyramidal lobe
The thyroid gland is covered by what fascia?
Pretracheal
What is the blood supply to the Thyroid gland?
Arterial supply
- Sup. thyroid a. (common carotid)
- Inf. thyroid a. (subclavian a.)
Venous drainage
- Sup. thyroid v. (into IJV)
- Mid. thyroid v. (into IJV)
- Inf. thyroid v. (into braciocephalic)
Describe the Parathyroid glands and their blood supply
Two pairs (sup. & inf.) of small glands usually on post. surface of Thyroid
Arteries
- Inf. thyroid a.
Veins
- Sup. Mid. Inf. thyroid v.
Describe the innervation of the Thyroid & Parathyroid glands
Thyroid branches of Cervical ggl. (Sympathetic)
What are the borders of the Posterior triangle?
Bound by:
- [Post. border] of SCM
- Ant. border of Trapezius
- Mid. 3rd of Clavicle
- Occipital bone
Roof
- Deep investing fascia
- SCM and Trapezius
Floor
- Prevertebral fascia
- Splenius capitis, levator scapulae, and scalene muscles
What are the 3 Subregions of the Posterior triangle?
Occipital triangle
- Accessory n.
- Brachial plexus
Omoclavicular triangle
- aka Major supraclavicular triangle
Minor supraclavicular triangle
- Inferior bulb of IJV
What does the Retromandibular fossa contain?
- Parotid gland
- Styloglossus, Stylohyoid, Stylopharyngeal muscles
- Stylomandibular & Stylohyoid ligaments
- Retromandibular v, maxillary & superficial temporal vessels
What are 2 Muscular branches of the Cervical Plexus?
Phrenic nerve (C3-5) to diaphragm
Ansa Cervicalis (C1-3) to infrahyoid muscle
What are 4 Cutaneous branches of the Cervical Plexus?
- Lesser occipital n. (C2)
- Greater auricular n. (C2-3)
- Transverse cervical n. (C2-3)
- Supraclavicular n. (C3-4)
At what level does Common Carotid bifurcate?
C3/4 vertebral level
or
Upper Margin of thyroid cartilage
Where is and what is the function of the Carotid Sinus?
- At the bifurcation of Common Carotid
- Contains Baroreceptors (measure BP)
- Innervated by CN IX (brings signal to nuc. solitarius -> vital centres in medulla -> dorsal nuc. of vagus)
Where is and what is the function of the Carotid Body?
- At the bifurcation of Common Carotid
- Contains Chemoreceptors (monitor O2, CO2, & pH)
- Innervated by CN IX (brings signal to nuc. solitarius -> vital centres in medulla)
What are the 3 Jugular Veins?
Int. Jugular v.
- Continuation of sigmoid sinus
- Exits at jugular foramen
- Enters carotid sheath, runs lateral to common carotid
- Joins subclavian v. to form brachiocephalic v.
Ext. Jugular v.
- Begins at angle of mandible, joining retromandibular & post. auricular v.
- Crosses over SCM
- Pierces investing fascia to enter & drain into subclavian v.
Ant. Jugular v.
- Arise near the hyoid bone & run on either side of the midline
- Drains into the external jugular vein
How should the anagesic ladder be used in Acute and Chronic pain?
Acute
- Start at the top and make your way down the ladder
Chronic
- Start at the bottom and make your way up the ladder
What is the ceiling effect of weak opioids?
Occurs when escalation of dose causes side effectd without improving analgesia (Plateaued efficacy)
List some Strong opioids
- Morphine
- Oxycodone
- Diamorphine (heroin)
- Fentanyl
- Remifentanil
- Methadone
- Pethidine (pupils dilate)
List some Weak opioids
- Codeine
- Dihydrocodeine
What is the Oral bioavailability of different Opioids?
Why is it relevant that Codeine is a pro-drug when considering administration?
Needs to be metabolised by liver CYP P450 enzymes to be activated
List some Opioid receptors
- Mu opioid receptors (MOP)
- Kappa (KOP)
- Delta (DOP)
- Nociception (NOP)
What are the 3 Endogenous opioids?
- Endorphin
- Encephalin
- Dynorphin
Describe action of opioid receptors
All are G-protein coupled receptors
Close presynaptic voltage gated Ca channels
- Reduces NT release
Open postsynaptic K channels
- Hyperpolarises neurone, inhibiting neural excitability
What are the CNS effects of opioids?
Analgesic effect
Sedative effect
Euphoria
- Potential for abuse
- Disinhibition of dopamine-containing neurones in ventral tegmental area
- Increased dopamine in nuc. accumbens
3rd cranial nerve nuc effects
- pin point pupils
What are some adverse effects of opioids?
Adverse effects will diminish as tolerance develops
- Constipation & Dry mouth are more resistant
Uticaria & Itch
- Histamine release
- Can be a disabling side effect, particularly w/ intrathecal injection
What are some Respiratory effects of opioids?
What are some Cardiovascular effects of opioids?
What are some GI and Urinary effects of opioids?
What are some of the Endocrine effects of opioids?
How are opiods metabolised?
What are some Opioid Antagonists?
What are some of the Withdrawal symptoms of Opioids?
What drug may be used to help take someone off of Heroin?
Methadone
How do Opioids cause Euphoria?
