Grover Flashcards
All or None Potentials
Action potentials; the strength of the signal is encoded by the frequency of repetition
Graded Potentials
can be synaptic or receptive; the strength of the signal is encoded by the amplitude of the potentials; this type of encoding is called amplitude modification
Integration/Trigger Zone
conversion zone, where amplitude modulated signals are converted to frequency modulated signals
Activators and Sensitizers
Activators: Potassium, Proton, Serotonin, Bradykinin, Histamine
Sensitizers: Serotonin, Prostaglandins, Leukotrienes, Substance P
Primary Hyperalgesia
occurs in tissue surrounding the site of injury; caused by peripheral release of chemical activators and sensitizers during the axon reflex
Secondary Hyperalgesia
surrounds the area of primary hyperalgesia; mediated by central nervous system
Allodynia
pain stimulation resulting from stimuli which are not normally capable of evoking pain
3 Classes of Endogenous Opioid Peptides in Nervous System
Enkephalins (pro-enkephalins)
Dynorphins (pro-dynorphins)
Endorphins (pro-opiomelanocortin)
Opioid Receptors: Three Classes and Function
All are metabotropic
Mu (enkephalins and endorphins)
Delta (enkephalins and endorphins)
Kappa (for dynorphins)
Opiate Drug Mechanism of Action
- Excitation of PAG projection neurons which then activate the descending serotonergic and noradrenergic pathways from the brainstem
- Inhibition of neurotransmission from nociceptors to dorsal horn projection neurons
Cyclo-oxygenase Inhibitors
inhibit formation of prostaglandins; reduce production of painful chemical stimuli in peripheral tissue
Ex: aspirin
NMDA Receptor Antagonists
NMDA receptors are common in pain pathways; antagonizing them can relieve pain
Ex: ketamine
