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Printable Handouts
Navigable Slide Index
- Introduction
- The history of the nociceptor concept
- The specificity hypothesis
- The origin of the term nociceptor
- Summary of the nociceptor concept
- Nociceptors and pain
- Schedule of a nociceptor
- The nociceptor neuron
- The CIPA syndrome
- Differentiation of nociceptor neurons
- Nociceptor neurons in the sensory ganglia
- Nociceptor classes
- Nociceptors with different conduction velocities
- The nociceptor terminal
- The transduction process
- The transient receptor potential channels
- Nociceptor modulation
- From generator potentials to action potentials
- Erythromelalgia
- Nociceptors in different tissues
- The nociceptor axons
- Axon reflex
- Microneurography
- C-nociceptor classes in humans
- Dichotomy of human C-fibers
- Outlook to pathophysiology
Topics Covered
- Nociceptors are the peripheral neurons subserving pain
- History of the concept
- Characterization of cellular mechanisms
- Plasticity as basis of clinical pain states
- Membrane receptors as basis of pain therapies
- Nociceptors in humans
Links
Series:
Categories:
Therapeutic Areas:
Talk Citation
Handwerker, H. (2009, January 26). Primary afferent nociceptors [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved October 12, 2024, from https://doi.org/10.69645/MTVL3749.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Hermann Handwerker has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
A selection of talks on Clinical Practice
Transcript
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0:04
The development of the
nociceptor concept.
As many scientists in
the previous centuries,
the famous philosopher
Rene Descartes
believed that pain can be
caused by the stimulation
of any nerve in our body.
The often recorded
drawing from his book
on the functioning of the
human body may illustrate this.
According to his assumption, pain
is induced by noxious stimuli which
over-excite all kinds of nerves.
Any nerve will transmit an
alarm signal into the brain,
which leads to pain.
This assumption has been
called intensity hypothesis.
0:48
In the late 19th century, the
German physiologist, Max von Frey,
challenged this assumption.
Nowadays, he's best known for the
development of the Von Frey hairs,
which allow application of
graded mechanical stimulation
to the body surfaces.
The figure in blue shows an original
depiction of this device in a paper
of Von Frey published in 1897.
The pointed stiff hair, nowadays,
usually a nylon filament
of defined diameter is
used, attached to a handle,
is pressed against the skin
so that it slightly bends.
The exerted pressure defines
the strengths of this stimulus.
With this simple
device, Von Frey made
the discovery which made him
famous, the pain points in the skin.
He writes in one of his papers: "It
is possible to stimulate the skin
in such a way as to
produce a painful sensation
with no proceeding or
accompanying pressure sensation.
That this can be done
leads to the conclusion
that pain is the result of
exciting special organs.
The pain points are a
sign of the irregular
distribution of specifically pain
sensitive organs over this skin."
The characteristic features
of the pain points are:
they can be distinguished
from touch, warmth and cold points.
The stimulation induces a sustained,
often increasing pain sensation.
And they require stronger
deformation than touch points.