نوروفیزیولوژی بی حسی های موضعی در دندانپزشکی

1. IN THE NAME OF GOD

2. ‫دندانپزشکی‬ ‫در‬ ‫موضعی‬ ‫حسی‬ ‫بی‬ ‫اصول‬
INTRODUCTION to LOCAL ANESTHESIA and
NEUROPHYSIOLOGY
‫نظری‬ ‫جراحی‬ ‫درس‬
‫حسینی‬ ‫هادی‬ ‫سید‬ ‫دکتر‬
‫صورت‬ ‫و‬ ‫فک‬ ‫جراحی‬ ‫متخصص‬
www.drhadihoseini.com
‫در‬ ‫اسالید‬ ‫دانلود‬:
http://www.slideshare.net/hadidezyan

3. ‫حسی‬ ‫بی‬ ‫ایجاد‬ ‫های‬ ‫روش‬
•‫فیزیکی‬ ‫ترومای‬
•‫سرما‬
•‫اکسیژن‬ ‫فقدان‬
•‫شیمیایی‬
•‫فنل‬ ‫و‬ ‫الکل‬
•‫حسی‬ ‫بی‬ ‫داروهای‬

4. ‫مطلوب‬ ‫حسی‬ ‫بی‬ ‫عامل‬ ‫یک‬ ‫خواص‬
•‫بافتی‬ ‫سمیت‬ ‫عدم‬ ‫و‬ ‫نسجی‬ ‫سازگاری‬
•‫دائمی‬ ‫تغییرات‬ ‫ایجاد‬ ‫عدم‬
•‫شرایط‬ ‫هر‬ ‫در‬ ‫تاثیر‬
•‫مطلوب‬ ‫اثر‬ ‫دوام‬ ‫و‬ ‫اثر‬ ‫زمان‬
•‫آلرژی‬ ‫بدون‬
•‫عامل‬ ‫مناسب‬ ‫پایداری‬

5. ‫با‬ ‫ابتدا‬ ‫حسی‬ ‫بی‬ ‫ایجاد‬ ‫برای‬ ‫عاملی‬ ‫هر‬ ‫از‬ ‫استفاده‬ ‫برای‬‫ید‬
‫داشت‬ ‫کافی‬ ‫اطالعات‬ ‫بدن‬ ‫در‬ ‫حس‬ ‫و‬ ‫اعصاب‬ ‫به‬ ‫نسبت‬

6. ‫عصبی‬ ‫پیام‬ ‫انتقال‬

7. ‫عصبی‬ ‫سلول‬
1) Dendritic Zone- free nerve endings;
most distal portion of the neuron
2) Axon- synapses with the CNS to transmit
input to the brain
3) Cell Body- provides metabolic support for
the entire neuron

8. Sensory Neurons (afferent)

9. Motor Neuron (efferent)

10. ‫عصبی‬ ‫سلول‬ ‫آکسون‬
•‫اکسوپالسم‬
•‫اکسولما‬
•‫سلولی‬ ‫غشای‬
•‫کانالی‬ ‫های‬ ‫پروتئین‬
•‫سل‬ ‫شوان‬
•‫میلین‬
•‫رانویه‬ ‫گره‬

11. The Membrane: Lipid Layer

12. ‫عصبی‬ ‫پیام‬ ‫انتقال‬ ‫الکتروفیزیولوژی‬
• Nerve resting potential is -70 mV; this is
produced by differing concentrations of ions
• on either side of the nerve membrane
• Interior of the nerve is negative compared to
the exterior before a stimulus excites the nerve

13. ‫پی‬ ‫انتقال‬ ‫الکتروشیمیایی‬ ‫های‬ ‫واکنش‬‫عصبی‬ ‫ام‬
•‫استراحت‬ ‫مرحله‬
–‫نفوذپذیر‬ ‫سدیم‬ ‫به‬ ‫کمی‬ ‫غشا‬
–‫نفوذپذیر‬ ‫پتاسیم‬ ‫به‬ ‫کامال‬ ‫غشا‬
–‫نفوذپذیر‬ ‫کلرید‬ ‫به‬ ‫کامال‬ ‫غشا‬
•‫غشایی‬ ‫تحریک‬
–‫دپالریزاسیون‬
–‫رپالریزاسیون‬

14. ‫عصب‬ ‫تحریک‬ ‫اول‬ ‫مرحله‬
‫تدریجی‬ ‫دپالریزاسیون‬
inside of nerve becomes less negative
‫آستانه‬ ‫پتانسیل‬
extremely rapid depolarization occurs from the falling
electrical potential
‫سریع‬ ‫دپالریزاسیون‬
interior is electricallypositive +40 mV and the outside is
negative
(-70 mv)

15. Resting to Threshold Potential

16. Threshold Potential to Rapid
Depolarization

17. ‫دوم‬ ‫مرحله‬
‫دپالریزاسیون‬ ‫از‬ ‫بعد‬ ‫رپالریزاسیون‬
Repolarization
‫کم‬ ‫ل‬‫سلو‬ ‫داخل‬‫الکتریکی‬‫پتانسیل‬‫شود‬ ‫می‬‫تر‬ ‫منفی‬ ‫کم‬
‫به‬ ‫داخل‬‫که‬ ‫مانی‬‫ز‬‫تا‬–70 mV‫برسد‬

18. ‫الکتروشیمیایی‬ ‫های‬ ‫واکنش‬
Depolarization Repolarization

19. ‫دپالریزاسیون‬
-excitation leads to increase in permeability of the
cell membrane to sodium ions
-transient widening of transmembrane ion channels
allow passage of the sodium ions
-rapid influx of sodium ions into the interior of the
nerve cell causes depolarization of the cell
membrane from resting to firing threshold which is
-50 to -60 mV

20. ‫شلیک‬ ‫آستانه‬ magnitude of the decrease
in negative trans-membrane potential that
is necessary to initiate an action potential
(impulse)
getting more positive with more influx of Na+

21. Firing Threshold

22. ‫میزان‬ ‫به‬ ‫غشایی‬ ‫بین‬ ‫منفی‬ ‫پتانسیل‬ ‫کاهش‬15mv
‫از‬ ‫یعنی‬-70‫به‬-55
‫از‬ ‫کمتر‬ ‫اختالف‬ ‫این‬ ‫اگر‬15‫نخواهد‬ ‫وجود‬ ‫ایمپالس‬ ‫باشد‬
‫داشت‬
‫آستانه‬ ‫این‬ ‫موضعی‬ ‫حسی‬ ‫بی‬ ‫داروی‬ ‫با‬ ‫عصب‬ ‫تماس‬
‫تحریک‬firing threshold‫برد‬ ‫می‬ ‫باال‬ ‫را‬
‫یعنی‬ ‫تحریک‬ ‫آستانه‬ ‫رفتن‬ ‫باال‬
more sodium must pass through the
membrane to decrease the negative
transmembrane potential
to a level where depolarization occurs

23. ‫میزان‬ ‫به‬ ‫غشایی‬ ‫بین‬ ‫منفی‬ ‫پتانسیل‬ ‫کاهش‬15mv
‫از‬ ‫یعنی‬-70‫به‬-55
‫از‬ ‫کمتر‬ ‫اختالف‬ ‫این‬ ‫اگر‬15‫داشت‬ ‫نخواهد‬ ‫وجود‬ ‫ایمپالس‬ ‫باشد‬
‫تماس‬‫تحریک‬ ‫آستانه‬ ‫این‬ ‫موضعی‬ ‫حسی‬ ‫بی‬ ‫داروی‬ ‫با‬ ‫عصب‬
firing threshold‫برد‬ ‫می‬ ‫باال‬ ‫را‬
‫یعنی‬ ‫تحریک‬ ‫آستانه‬ ‫رفتن‬ ‫باال‬
more sodium must pass through the membrane to
decrease the negative transmembrane potential
to a level where depolarization occurs

24. ‫افزایش‬ ‫با‬ ‫آمد‬ ‫بدست‬ ‫تحریک‬ ‫آستانه‬ ‫وقتی‬
‫شود‬ ‫می‬ ‫وارد‬ ‫بسرعت‬ ‫سدیم‬ ‫غشا‬ ‫نفوذپذیری‬
depolarization lasts ~ .3 msec

25. ‫رپالریزاسیون‬
The action potential is terminated
when the membrane repolarizes; this
is caused by the inactivation of
increased permeability to sodium

26. Repolarization

27. Sodium is moved out of the cell using ATP and
the sodium pump
Repolarization requires ~ .7 msec

28. ‫مطلق‬ ‫ناپذیری‬ ‫تحریک‬
•‫غشایی‬ ‫تحریک‬ ‫به‬ ‫پاسخ‬ ‫عدم‬
Absolute Refractory Period
•‫آید‬ ‫می‬ ‫نسبی‬ ‫دوره‬ ‫بالفاصه‬ ‫ان‬ ‫از‬ ‫بعد‬
Relative Refractory Period
•‫عصب‬ ‫کامل‬ ‫رپالریزاسیون‬ ‫نهایت‬ ‫در‬ ‫و‬

29. ‫غشایی‬ ‫های‬ ‫کانال‬
•‫سدیم‬ ‫های‬ ‫کانال‬

30. Sodium channels line the excitable nerve membrane
which are lipoglycoproteins situated firmly in the
membranes
Sodium passes through the channels 12 times easier
than potassium
Sodium ions are “thinner” than potassium or chloride
ions and should therefore move easily down
concentration gradients through membrane channels
into the nerve cell, however:

31. Potassium and chloride can pass through these gated
channels
During depolarization the gated transmembrane sodium
channels change their configuration to allow the sodium
ions to enter the cell

32. ‫ایمپالس‬ ‫انتقال‬
Activation of an action potential by a stimulus
Disruption of the resting nerve membrane potential
Interior of the cell goes from negative (–70 mV) to positive (+40 mV)
Exterior of the cell changes from positive to negative
Local currents begin flowing between the depolarized segment and the
adjacent resting area
Local currents flow from positive to negative extending for several mm
along the nerve membrane
As a result, the interior of adjacent areas become less negative and the
exterior becomes less positive

33. ‫ایمپالس‬ ‫انتقال‬
Transmembrane potential decreases approaching firing
threshold for depolarization
When transmembrane potential decreases by 15mV from
resting potential, firing threshold is reached and rapid
depolarization occurs
The newly depolarized segment sets up local currents and
it all starts over again
Newly depolarized segments return to resting state after
absolute and relative refractory periods

34. Impulse Propagation

35. ‫ایمپالس‬ ‫انتقال‬
‫وجود‬ ‫بعلت‬absolute‫و‬relative refractory periods
‫میشو‬ ‫انجام‬ ‫رونده‬ ‫جلو‬ ‫بصورت‬ ‫فقط‬ ‫عصبی‬ ‫پیام‬ ‫انتقال‬‫د‬

36. ‫ایمپالس‬ ‫انتشار‬
Unmyelinated Nerves
-high electrical resistance cell membrane
-slow forward “creeping” spread of impulses
-conduction of unmyelinated C fibers is1.2 m/sec

37. Myelinated Nerves
-insulating myelin separates the extra/intracellular charges
-the farther apart the charges the smaller the current necessary
to charge the membrane
-current leaps from node to node  saltatory conduction

38. if conduction of an impulse is blocked at one node, the local
current skips that node and continues to the next node

39. ‫حداقل‬8‫تا‬10‫بی‬ ‫ماده‬ ‫با‬ ‫باید‬ ‫عصب‬ ‫طول‬ ‫از‬ ‫م‬ ‫م‬
‫باشد‬ ‫داشته‬ ‫تماس‬ ‫حسی‬

40. ‫حسی‬ ‫بی‬ ‫داروهای‬ ‫اثر‬ ‫جایگاه‬ ‫و‬ ‫نحوه‬
‫داروی‬‫مقاب‬ ‫عصبی‬ ‫شدن‬ ‫تحریک‬ ‫با‬ ‫زیر‬ ‫طرق‬ ‫به‬ ‫حسی‬ ‫بی‬‫له‬
‫کند‬ ‫می‬
•‫استراحت‬ ‫پتانسل‬ ‫در‬ ‫تغییر‬
•‫تحریک‬ ‫سطح‬ ‫و‬ ‫آستانه‬ ‫پتانسیل‬ ‫در‬ ‫تغییر‬
•‫دپالریزاسیون‬ ‫میزان‬ ‫کاهش‬
•‫رپالریزاسیون‬ ‫کردن‬ ‫طوالنی‬

41. Because of local anesthetics, cellular
depolarization is not sufficient to
reduce the membrane potential of a
nerve fiber to its firing threshold and a
propagated action potential
does not develop

42. ‫حسی‬ ‫بی‬ ‫اثر‬ ‫مکانیسم‬ ‫های‬ ‫تئوری‬
‫کند‬ ‫می‬ ‫اثر‬ ‫ای‬ ‫ناحیه‬ ‫چه‬ ‫در‬ ‫موضعی‬ ‫حسی‬ ‫بی‬ ‫داروی‬
•‫غشایی‬ ‫انبساط‬ ‫تئوری‬
•‫اختصاصی‬ ‫گیرنده‬ ‫تئوری‬

43. ‫غشایی‬ ‫انبساط‬ ‫تئوری‬

44. ‫اختصاصی‬ ‫رسپتور‬ ‫تئوری‬ Specific Receptor Theory
local anesthetics act by binding to specific receptors on the sodium channel
the action of the drug is direct
a specific receptor site for local anesthetics exists in the sodium channel
Therefore: no impulse conduction

45. ‫طو‬ ‫در‬ ‫سدیم‬ ‫انتشار‬ ‫از‬ ‫تایی‬ ‫سه‬ ‫آمین‬ ‫موضعی‬ ‫های‬ ‫ی‬ ‫حس‬ ‫بی‬‫ل‬
‫کند‬ ‫می‬ ‫ی‬‫جلوگیر‬ ‫عصبی‬ ‫تحریک‬

46. ‫موضعی‬ ‫های‬ ‫حسی‬ ‫بی‬ ‫اثر‬ ‫مکانیسم‬
1) Displacement of calcium ions from the sodium channel receptor site
2) Binding of the local anesthetic molecule to this receptor site
3) Blockade of the sodium channel
4) Decrease in sodium conductance
5) Depression of the rate of electrical depolarization
6) Failure to achieve the threshold potential level (firing level)
7) Lack of development of propagated action potentials
8) Conduction blockade

47. Nerve block produced by local anesthetic is
called a nondepolarizing nerve block