Ch1 BB AALA Flashcards
- What is the IASP?
International Association for the Study of Pain
- What is the IASP definition of pain?
- “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”
- What is a more animal specific definition of pain?
- “an aversive sensory, emotional experience representing an awareness by the animal of damage or threat to the integrity of its tissues; it changes the animal’s physiology and behavior to reduce or avoid damage, reduce the likelihood of recurrence, and to promote recovery; non-functional pain occurs when the intensity or duration of the experience is not appropriate for the damage sustained and when physiological and behavioral responses are unsuccessful in alleviating it.”
- What is acute pain?
- Acute pain- has proximate cause, often serves as an essential protective function by associating potentially damaging noxious stimuli with an unpleasant sensation
- Acute pain can be further characterized as _________ or __________.
- physiologic or clinical
- Differentiate between the two classifications of acute pain.
- physiologic- early-warning system that aids in protecting body from tissue damage by physical, thermal, or chemical threats, initiated by activation of high-threshold nociceptive neurons, highly localized, transient, initiates physiologic and avoidance behaviors accompanied by protective reflexes; clinical- prolonged unpleasant sensations arising from significant tissue damage, induces augmented or abnormal signal processing, may be spontaneous, may be characterized by hypersensitivity, hyperalgesia, & allodynia, & pain surrounding noninjured tissues
- What is chronic pain?
- “pain which persists past the normal time of healing”, pain continues beyond the stage where it is useful to protect the region, or is persistent and may not have a clearly identifiable cause
- The IASP regards _____ months of pain as the most expedient point at which transition from acute to nonmalignant pain can be defined.
3 months
- What is pain threshold?
- least experience of pain an individual can recognize
- True or False: Sex has been demonstrated to influence pain thresholds in animals.
- False- has not been conclusively demonstrated
What is pain tolerance?
- the greatest level of pain an individual is willing to tolerate
- _____________ is an exaggerated response to a stimulus that would normally be painful.
- hyperalgesia
- _____________ refers to reduced threshold to noxious stimuli.
- hypersensitivity
- What is allodynia?
- pain induced by a non-noxious stimulus
- What is analgesia?
- absence of pain in response to stimulation that would normally be painful
- _____________ is the sensation of noxious stimuli.
nociception
- What is the important distinction between nociception and pain?
- nociception includes neurobiological processes by which noxious stimuli are encoded as neural impulses and sent to the brain; pain is the cognitive and emotive interpretation of the sensation as a hurtful or unpleasant experience
- ___________ is the process of converting noxious thermal, mechanical, or chemical stimuli into an action potential
transduction
- True or False: The frequency and duration of the action potential is proportional to the intensity and duration of the stimulus.
True
- True or False: Most nociceptors are unimodal.
- False- polymodal
- What are “silent” nociceptors?
- nociceptors that express transducers with such high activation thresholds that they are only activated when sensitized by tissue injury
- List the major transducer types.
- transient receptor potential ion channels, ATP-gated ion channels, and acid-sensing ion channels
- _______ respond to thermal, chemical, and possibly mechanical stimuli.
transient receptor potential ion channels
- _________ are released in response to mechanical forces, inflammation, and nerve damage.
ATP-gated ion channels
- _________ transduce innocuous mechanical stimuli such as touch.
acid-sending ion channels
- What is transmission?
- the process by which primary afferent sensory neurons propagate action potentials to the spinal cord
- What 5 things are nociceptive neurons characterized by?
- size, myelination, peptide content, receptive characteristics, and site of termination in the spinal cord
- _______ fibers are thinly myelinated, have intermediate velocities, punctate receptive fields, and respond to thermal and mechanical stimuli.
- Aδ
- _______ fibers constitute the majority of peripheral nociceptive fibers, have small unmyelinated axons, wide receptive fields, and are polymodal.
C
- ______ fibers are large, myelinated, and have fast conduction velocities.
- Aβ
- True or False: All neurons express voltage-gated sodium ion channels.
True
- What is projection, and where does it start?
- process of conveying information through the spinal cord to the brain, starts in the dorsal horn
- Primary afferent nociceptive neurons connect with interneurons where in the dorsal spinal cord?
a. lamina I
b. substantia gelatinosa (II, IIa)
c. lamina V
d. all of the above
e. none of the above
- d- all of the above
- What type of neurons do dorsal horn projections code into?
nociceptive-specific
wide dynamic range
non-nociceptive
- ____________ neurons are innervated by Aδ and C fibers and code localizing and qualitative information about noxious stimuli.
- nociceptive-specific
- __________ neurons are innervated by C, Aδ, and Aβ fibers and convey the intensity of noxious and innocuous mechanical, thermal, and chemical stimuli.
- wide dynamic range
- ________ fibers code innocuous thermal and mechanical information from Aβ and Aδ fibers.
- non-nociceptive
- What may be the four most important spinal tracts involved in pain?
- spinothalamic, spinoreticular, spinomesencephalic, and spinohypothalamic tracts
- True or False: In contrast to humans and NHP, other animals do not have a bilateral, diffuse and multisynaptic nociceptive pathway in the spinal cord.
- False- other animals DO have bilateral, diffuse, multisynaptic pathway in contrast to humans and NHP
- The ________ has long been considered the key relay for receiving and integrating spinal nociceptive input and projecting that information to cortical and subcortical areas of the brain.
- thalamus
- What is modulation?
- the process by which nociceptive information from primary afferents is inhibited or augmented
- True or False: Most dorsal horn neurons are inhibitory interneurons.
True
- What happens when inhibitory interneurons are activated?
- What is the primary excitatory neurotransmitter release by nociceptive terminals?
glutamate
- Glutamate preferentially binds to what receptor(s)?
kainate
AMPA
NMDA
- What is the principal inhibitory neurotransmitter in the nervous system?
GABA
- GABA’s actions are mediated by _______ and _______ receptor subtypes.
- What happens when these receptors are activated?
- GABAA- hyperpolarizes cell, decreasing excitation; GABAB- reduces release of glutamate, substance P, and calcitonin gene-related product
- What neurotransmitter(s) is/are most critical to descending antinociception?
Serotonin
Norepinephrine
- True or False: Norepinephrine stimulates the release of GABA and glycine, reduces glutmate release from primary afferents and reduces excitation of projection neurons.
True
- True or False: Both noxious and non-noxious stimuli elicit the same type of unlocalized body responses in altricial rats.
True
- True or False: In rats, the descending inhibitory systems that help fine-tune responses are mature and functional at birth.
- False- immature at birth and not functional until 3 wks after birth
- The _______________ is the primary system affecting the neuroendocrine response to pain.
- hypothalamic-pituitary-adrenal axis
- True or False: Responses to pain are the mirror images of those elicited by restraint or other stressors.
- False- are not mirror image
- The neuroendocrine and sympathetic nervous system responses to pain are initiated by:
a. neuronal stimulation through direct and indirect connection with nociceptive pathways
b. IL-1
c. TNF
d. All of the above
e. None of the above
- d- all of the above
- Activation of the hypothalamic-pituitary-adrenal axis by acute pain results in the release of:
corticotrophin-releasing hormone
antidiuretic hormone
prolactin & adrenocorticoropic hormone
β-endorphins
glucocorticoids
- True or False: Pain causes increased heart rate, blood pressure, cardiac output, and systemic vascular resistance.
True
- True or False: Pain in human thoracic surgery patients, has been shown to decrease tidal volume, functional residual capacity, and cause ventilation-perfusion mismatch.
True
- Name 3 miscellaneous effects of pain
glucose intolerance
ileus
sleep disturbance
- What does neural plasticity refer to?
- when neurons alter their structure/function in response to stimulation or activation
- True or False: Prostaglandin E2, Histamine, and Nerve growth factor are algogens and cause sensitization.
- False- sensitization, not algogens
- What is “wind-up”?
- progressive increase in action potential frequency generated by closely repeated constant pulses of electricity
- True or False: Wind-up is necessary and sufficient for central sensitization to occur.
- ________________ contributes to primary hyperalgesia, and is the only mechanism by which secondary hyperalgesia and secondary allodynia occur.
- Central sensitization is not a completely neuronal event, and may depend upon _____________ activation.
- glial cell
- The glial model of central sensitization suggests that the CNS synapses have a tetrapartite structure, comprised of:
microglia
astrocytes
pre-synaptic neurons
post-synaptic neurons
- True or False: Over a period of hours-days, central sensitization switches from transcription-and-translation-dependent processes to activity-dependant processes.
- False- switches from activity-dependent to transcription-and-translation dependent
- What are the cardinal signs of chronic pain?
- allodynia, hyperalgesia, and spontaneous pain
- True or False: Once astrocytes are activated, inhibiting microglial cells has no effect on pain.
True
- Which voltage-gated sodium channels have been implicated in the pathogenesis of both neuropathic and inflammatory chronic pain?
1.3, 1.7, and 1.8
- Altered expression and distribution of sodium ion channels leads to the generation of _________________ in the absence of stimuli.
- spontaneous (ectopic) impulses
- Voltage gated _______________ (sodium or calcium, choose one) channels appear to regulate neurotransmitter release.
calcium
- True or False: Loss of inhibitory interneurons appears to be mediated by glutamate receptor 5 and caspase-3 activity.
True
- What is phenotypic switching?
induced expression of nociceptive-related ion channels, molecules, and receptors not normally found in non-nociceptive sensory neurons, and novel up-or down regulation of similar molecules in nociceptive neurons
- True of False: Most chronic pain encountered in veterinary medicine is likely neuropathic, inflammatory, or neoplastic in origin
True
What are definitions of neuropathic pain?
- “pain initiated or caused by a primary lesion or dysfunction of the nervous system”, “pain caused by a lesion of the peripheral or central nervous system (or both) manifesting with sensory symptoms and signs”
- Which of the following is NOT an etiology responsible for neuropathic pain?
a. chemotherapy induced polyneuropathy
b. diabetes
c. herpes virus
d. multiple sclerosis
e. osteoarthritis
- e- osteoarthritis
- How does chronic inflammatory pain develop?
- from chemicals (algogens, sensitizers, immunomodulators) released by immunocytes infiltrating injured or diseased tissue
- Which of the following is NOT an example of a disease associated with chronic inflammatory pain?
a. herpes virus
b. osteoarthritis
c. endometriosis
d. feline lower urinary tract disease
e. ulcerative dermatitis
- a- herpes virus