هﺮــﮔ یﺎﻬﻟﻮﻠﺳ ﯽــﻤﯿﺴﻠﮐ یارﺬﮔ ﯽــﻧﻮﯾ نﺎﯾﺮﺟ ندﺮﮐ دوﺪﺴﻣ ﺮﺑ ﻞــﮑﯿﻧ ﺮــﯿﺛﺄﺗ شﻮﮔﺮﺧ ﺐﻠﻗ ﻢﻟﺎﺳ و هدرﻮﺨﻧ ﺖﺳد یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ
I ماﺮﻤﮑﯿﻧ ﺎﺿرﺪﻤﺤﻣ ﺮﺘﮐد*
II ﺖﯾﻮﺑدرﺎﭽﯾر کرﺎﻣ ﺮﺘﮐد
ﻪﻣﺪﻘﻣ ﻪـــﻠﻤﺟ زا ناراﺪﻧﺎﺘــﺴﭘ ﺐــﻠﻗ یﺰﯿــﻠﻫد ـ ﯽــﺳﻮﻨﯿﺳ هﺮﮔ یژﻮﻟﻮﯾﺰﯿـﻓوﺮﺘﮑﻟا و ﯽـﺳﺎﻨﺷ ﺖﻓﺎـﺑ ﺮـﻈﻧ ﻪــﻄﻘﻧ زا شﻮﮔﺮﺧ ﻪـﮐ ﺪـﻧاهداد نﺎــﺸﻧ ﺖﯾﻮﺑ و ماﺮﻤﮑﯿﻧ (1-8)ﺖﺳا ﻦﮕﻤﻫﺎﻧ ﯽﺘﻓﺎﺑ و ﯽـﻄﯿﺤﻣ ،یﺰـﮐﺮﻣ ﻪـﻧﺎﮔ ﻪـﺳ ﯽـﺣاﻮﻧ ﻞـﻤﻋ ﻞﯿــﺴﻧﺎﺘﭘ ﻞﮑﺷ 9 رد شﻮـﮔﺮـﺧ ﺐـﻠﻗ رد یﺰﯿـﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮــﮔ ﯽﻨﯿﺑﺎﻨﯿﺑ ﺪـﻧاﻮﺗﯽﻣ توﺎـﻔﺗ ﻦـﯾا .(9)ﺪـﺷﺎﺑﯽﻣ توﺎـﻔﺘﻣ ًﻼﻣﺎــﮐ ﻪﺼﺨﺸﻣ ﯽـﻧﻮﯾ یﺎﻬـﻧﺎﯾﺮﺟ دﻮـﺟو مﺪــﻋ ﺎﯾ دﻮﺟو رد توﺎﻔﺗ ﻪﺑ طﻮﺑﺮﻣ ﺚـﺤﺑ ﮏـﯾ دﻮــﺧ ﻪﮐ ﺪﺷﺎﺑ رﻮﮐﺬﻣ ﻪﻧﺎﮔ ﻪﺳ ﻖﻃﺎﻨﻣ رد ﻒﻠﺘﺨﻣ “If” ﯽـﻧﻮﯾ نﺎـﯾﺮﺟ ﺶـﻘﻧ .(10)دﻮــﺷﯽﻣ بﻮﺴﺤﻣ ﺪﯾﺪﺟ ًﺎﺘﺒﺴﻧ
ﻪـــﯿﺣﺎﻧ رد (hyperpolarization activated current)
هﺮــــﮔ یﺰــﮐﺮﻣ ﻪـــــﯿﺣﺎﻧ زا ﺮــــــﺘﻤﻬﻣ ﯽــــﻠﯿﺧ ﯽـﻄﯿﺤﻣ .ﺖﺳا یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ دوﺪـﺴﻣ ﻪـﮐ ﺪـﻧاهداد نﺎــﺸﻧ (12 و11)ﺶﻧارﺎﮑﻤﻫ و ماﺮﻤﮑﯿﻧ
ﻞﯿـﺴﻧﺎﺘﭘ ﺮـﺑ یﺮﺘــﺸﯿﺑ و ﺮﺘﮔرﺰﺑ تاﺮﺛا رﻮﮐﺬﻣ نﺎﯾﺮﺟ ندﺮﮐ ﺎـﺑ ﻪـﮐ ﯽﻧﺎـﻣز ،ﯽـﻄﯿﺤﻣ ﻪــﯿﺣﺎﻧ رد نآ ﺖﯿﻟﺎﻌﻓ و یﺮﮑﯿﻣ ﺲﯿﭘ دراد دﻮــــﺷ ﻪـﺴﯾﺎﻘﻣ یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ یﺰﮐﺮﻣ ﻪﯿﺣﺎﻧ ﯽـــﺗاذ یﺮـﮑﯿﻣ ﺲـﯿﭘ ﺮــﺗدﺎﯾز ﺖـــﯿﻟﺎﻌﻓ عﻮـﺿﻮﻣ ﻦـــﯾا ﻪـﮐ .ﺪﻨﮐﯽﻣ ﻪﯿﺟﻮﺗ ار ﯽـﻄﯿﺤﻣ ﻪﯿﺣﺎﻧ یﺎﻬﻟﻮﻠﺳ ﺮـﻫ ﻪــﮐ ﺪـــــﻧاهداد نﺎﺸﻧ (13)ﺶـــﻧارﺎﮑﻤﻫ و Bouman هﺮــﮔ ﯽـــﻄﯿﺤﻣ ﻪـــﯿﺣﺎﻧ ﺖـــﻤﺳ ﻪـﺑ یﺰـﮐﺮﻣ ﻪـﯿﺣﺎﻧ زا ﻪـﭼ ﺎـﯾ K یﺮـــــﯿﺧﺄﺗ هﺪــﻨﻨﮐ ناﺮﺒﺟ نﺎﯾﺮﺟ ﺶـــﻘﻧ ﻢـــﯾورﯽﻣ ﺮـــــــــﺘﻤﻬﻣ (delayed-rectifying k+ current)Ikr
نﺎــﯾﺮﺟ ﻪــﮐ ﺖــﺳا هﺪــﺷ شراﺰـــﮔ ﻦـﯿﻨﭽﻤﻫ .دﻮــــﺷﯽﻣ ﺎﻣا دراد دﻮـﺟو یﺰـﮐﺮﻣ ﻪـﯿﺣﺎﻧ رد (sustained current)Ist
هﺪﯿﮑﭼ
و ﺮـﮑﻔﺗ .ﺖـﺴﯿﻧ ﺖـﺧاﻮﻨﮑﯾ ﮏـﯾژﻮﻟﻮﯾﺰﯿـﻓوﺮﺘﮑﻟا و ﯽﺘﻓﺎـﺑ ﺮــﻈﻧ ﻪﻄﻘﻧ زا ناراﺪﻧﺎﺘﺴﭘ ﺐﻠﻗ یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ ﯽـﮑﯾ .ﺖــﺳا هﺪﺷ عوﺮﺷ ﯽﮔزﺎﺗ ﻪﺑ دﻮﺷﯽﻣ ﯽﮑﯾﺮﺘﮑﻟا ﺖﯿﻟﺎﻌﻓ رد توﺎﻔﺗ ﺐﺟﻮﻣ ﻪﮐ ﯽﻧﻮﯾ یﺎﻬﻧﺎﯾﺮﺟ ﻪﻨﯿﻣز رد ﻖﯿﻘﺤﺗ نﺎﯾﺮﺟ ﺪﺷﺎﺑ ﻪﺘﺷاد ﺶﻘﻧ ﻞﻤﻋ ﻞﯿﺴﻧﺎﺘﭘ رد یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ ﺰﮐﺮﻣ رد ﺪﺳرﯽﻣ ﺮﻈﻧ ﻪﺑ ﻪﮐ ﯽﻧﻮﯾ یﺎﻬﻧﺎﯾﺮﺟ زا یﺮﮑﯿﻣ ﺲﯿﭘ ﺖﯿﻟﺎﻌﻓ ﺮﺑ رﻮﮐﺬﻣ نﺎﯾﺮﺟ ندﺮﮐ دوﺪﺴﻣ ﺮﯿﺛﺄﺗ ﻪﻌﻟﺎﻄﻣ ﻦﯾا رد ﻪﮐ ﺪﺷﺎﺑﯽﻣ ICaT ﺎﯾ ﯽﻤﯿﺴﻠﮐ یارﺬﮔ ﯽﻧﻮﯾ 40 ﻂـﺳﻮﺗ شﻮـﮔﺮـﺧ هدرﻮـﺨﻧ ﺖـﺳد و ﻢﻟﺎـﺳ ﺐﻠﻗ یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ زا ﻪﻧﻮﻤﻧ 9 یﺰﮐﺮﻣ و ﯽﻄﯿﺤﻣ ﯽﺣاﻮﻧ ﺮـﺑ ار یرادﯽـﻨﻌﻣ ﺮﯿـﯿﻐﺗ ﻞـﮑﯿﻧ دراﻮـﻣ ﻪــﻤﻫ رد .ﺖﻓﺮﮔ راﺮﻗ ﯽﺳرﺮﺑ درﻮﻣ ﻪﻘﯿﻗد 30 تﺪﻣ ﻪﺑ و ﻞﮑﯿﻧ رﻻﻮﻣ وﺮﮑﯿﻣ ﺖـﺤﺗ ﻪـﮐ دراد دﻮــﺟو لﺎﻤﺘﺣا ﻦﯾا .داﺪﻧ نﺎﺸﻧ ﯽﻄﯿﺤﻣ ﻪﯿﺣﺎﻧ رد و یﺰﮐﺮﻣ ﻪﯿﺣﺎﻧ رد ﻞﻤﻋ ﻞﯿﺴﻧﺎﺘﭘ ﻞﮑﺷ تﺎﺼﺘﺨﻣ ﻦـﮑﻤﻣ ﻦـﯿﻨﭽﻤﻫ .ﺪـﺷﺎﺑ لﺎــﻌﻓ ﺮﯿﻏ رﻮﮐﺬﻣ ﻪﯿﺣﺎﻧ ود ﺮﻫ رد ICa T ﯽﻤﯿﺴﻠﮐ یارﺬﮔ ﯽﻧﻮﯾ نﺎﯾﺮﺟ ﮏﯾژﻮﻟﻮﯾﺰﯿﻓ ﻂﯾاﺮﺷ اﺪـﯿﭘ ﺖﻔﯿـﺷ یﺮــﮑﯿﻣ ﺲﯿﭘ ﺖﯿﺻﺎﺧ ﻞﮑﯿﻧ رﻮﻀﺣ رد ﺎﻣا ﺖﺳا ﻢﻬﻣ ﺰﮐﺮﻣ رد ﺚﺤﺑ درﻮﻣ نﺎﯾﺮﺟ ﻪﮐ دﻮﺷ ﻪﺘﻔﮔ ﺖﺳا .ددﺮﮔﯽﻣ نﺎﻬﻨﭘ ﻞﮑﯿﻧ ﺮﺛا و هدﺮﮐ ﻞﮑﯿﻧ – 3 (ICa T) ﯽﻤﯿﺴﻠﮐ یارﺬﮔ ﯽﻧﻮﯾ نﺎﯾﺮﺟ – 2 یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ – 1 :ﺎﻫهژاوﺪﯿﻠﮐ
.(لﻮﺌﺴﻣ ﻒﻟﻮﻣ*)ناﺮﻬﺗ ،ناﺮﯾا ﯽﻧﺎﻣرد ـ ﯽﺘﺷاﺪﻬﺑ تﺎﻣﺪﺧ و ﯽﮑﺷﺰﭘ مﻮﻠﻋ هﺎﮕﺸﻧاد ،یﺮﻈﻧهﺎﺷ ﺪﯿﻬﺷ نﺎﺑﺎﯿﺧ ،ردﺎﻣ ناﺪﯿﻣ ،ﯽﺸﺨﺒﻧاﻮﺗ هﺪﮑﺸﻧاد ،یژﻮﻟﻮﯾﺰﯿﻓ هوﺮﮔ رﺎﯾدﺎﺘﺳا (I
.نﺎﺘﺴﮕﻧا ،زﺪﯿﻟ هﺎﮕﺸﻧاد ،یژﻮﻟﻮﯾﺰﯿﻓ نﺎﻤﺗرﺎﭘد ،یژﻮﻟﻮﯾﺰﯿﻓ رﺎﯾدﺎﺘﺳا (II
هﺮـﮔ رد .(15 و14)دراﺪـﻧ دﻮـﺟو ﯽـﻄﯿﺤﻣ ﻪــﯿﺣﺎﻧ یﺎﻬﻟﻮﻠﺳ رد یﺎـــــﻬﭘﻮـﺗ رد ﺰـــــﯿﻧ و ﻢــــﻟﺎﺳ یﺰـــﯿﻠﻫد ـ ﯽـــﺳﻮﻨﯿﺳ ،یﺰﯿـــﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮـﮔ زا هﺪـﺷ ﻪـﯿﻬﺗ ﯽـــﺘﻓﺎﺑ ﮏـﭼﻮـﮐ ﻞـــﻤﻋ ﻞﯿـــﺴﻧﺎﺘﭘ ﯽــــــﮔﺪﻧورﻻﺎــﺑ ﺖــــﻋﺮﺳ ﻢــــﻤﯾﺰﮐﺎﻣ
ﻪـــﯿﺣﺎﻧ زا ﺞــﯾرﺪﺘﺑ (maximum upstroke velocitiy)
ﺶـﯾاﺰﻓا یﺰﯿـﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮــﮔ ﯽﻄﯿﺤﻣ ﻪﯿﺣﺎﻧ ﻪﺑ یﺰﮐﺮﻣ ﻪﻧﺎـﺸﻧ هﺮــﮔ ﯽﻄﯿﺤﻣ ﻪﯿﺣﺎﻧ رد ﺶﯾاﺰﻓا ﻦﯾا ﻪﮐ (16-19)ﺪﺑﺎﯾﯽﻣ هدﺎـﻣ ﻪـﺑ سﺎـﺴﺣ (INa) ﯽﻤﯾﺪــﺳ ﻊﯾﺮﺳ ﯽﻧﻮﯾ نﺎﯾﺮﺟ ﺶﯾاﺰﻓا
ﻦـــﯿﻨﭽﻤﻫ .ﺖـﺳا (fast inward sodium current)TTX
ﺖﻋﺮــﺳ ﺶﻫﺎــﮐ یﺰــﮐﺮﻣ ﻪــﯿﺣﺎﻧ رد ﻪـــﮐ ﺪـــﺷ هﺪﻫﺎـﺸﻣ ﯽﻤﯿـﺴﻠﮐ یارﺬـﮔ ﯽــﻧﻮﯾ نﺎﯾﺮﺟ دﻮﺟو ﻪﺑ طﻮﺑﺮﻣ ﯽﮔﺪﻧورﻻﺎﺑ .(20)ﺪﺷﺎﺑﯽﻣ (Trasient Ca+2 current)ICa T
ﺰﮐﺮﻣ رد ﯽﻤﯿﺴﻠﮐ یارﺬﮔ ﯽﻧﻮﯾ نﺎﯾﺮﺟ ﻪﮐ ﺪﺳرﯽﻣ ﺮﻈﻧ ﻪﺑ ﺎـﺑ لﺎــﻤﺘﺣا ﻦﯾا و دراد ﺶﻘﻧ یﺮﮑﯿﻣ ﺲﯿﭘ ﺐﯿﺷ دﺎﺠﯾا رد هﺮﮔ ﻂــﺳﻮﺗ ﺐـﺳﺎﻨﻣ ﯽﯾﺎﯿﻤﯿـﺷ داﻮـﻣ ﻂـﺳﻮﺗ نآ ندﺮـﮐ دوﺪـﺴﻣ .ﺖﺳا هﺪﯾدﺮﮔ ﯽﺳرﺮﺑ ناﺮﮕﯾد ندﺮـﮐ دوﺪـﺴﻣ ﺖﻬـﺟ ﻪـﮐ ﺪــﺷﺎﺑﯽﻣ یداﻮﻣ ﻪﻠﻤﺟ زا ﻞﮑﯿﻧ ﯽــﺳﻮﻨﯿﺳ هﺮـﮔ هﺪـﺷ ﻪـﻟوﺰﯾا یﺎﻬﻟﻮﻠـﺳ رد رﻮـﮐﺬﻣ نﺎـﯾﺮﺟ مﺎــﺠﻧا یﺎﻬﯿﺳرﺮﺑ رد ﺎﻣا (20-22)ﺖﺳا هﺪﺷ هدﺎﻔﺘﺳا یﺰﯿﻠﻫﺪـ هﺮﮔ رد ﻞﮑﯿﻧ ﻂﺳﻮﺗ نﺎﯾﺮﺟ ﻦﯾا رﺎﻬﻣ ﺖﻬﺟ ﯽﻘﯿﻘﺤﺗ ﭻﯿﻫ هﺪﺷ ﻪـﺘﻓﺮﮕﻧ ترﻮـﺻ ﻢﻟﺎــﺳ و هدرﻮﺨﻧ ﺖﺳد یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ ﺮـﺑ ﻞــﮑﯿﻧ ﺮﺛا ﯽﺳرﺮﺑ رﻮﻈﻨﻣ ﻪﺑ ﺮﺿﺎﺣ ﻪﻌﻟﺎﻄﻣ ﻦﯾاﺮﺑﺎﻨﺑ ﺖﺳا ﺖـﺒﺛ زا ﺲـﭘ) ﯽﻤﯿـﺴﻠﮐ یارﺬـﮔ ﯽـﻧﻮﯾ نﺎــﯾﺮﺟ ندﺮﮐ دوﺪﺴﻣ یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ ﯽﻄﯿﺤﻣ و یﺰﮐﺮﻣ ﻪﯿﺣﺎﻧ زا ﯽﮑﯾﺮﺘﮑﻟا نآ ﯽﻃ ﻪﮐ ﺪﺷ مﺎﺠﻧا (لﺮﺘﻨﮐ ناﻮﻨﻋ ﻪﺑ هدرﻮﺨﻧ ﺖﺳد و ﻢﻟﺎﺳ سﺎـــﺳاﺮﺑ) ﻪـــﻘﯿﻗد 30 تﺪـﻣ ﻪـﺑ ﻞــﮑﯿﻧ رﻻﻮـﻣوﺮﮑﯿﻣ 40 زا نﺎـﯾﺮﺟ ﻦـــــﯾا ﯽــﻟﺎﻤﺘﺣا ﺶـﻘﻧ ﺎﺗ ﺪـــﯾدﺮﮔ هدﺎﻔﺘﺳا (تﻻﺎﻘﻣ ﺺﺨـﺸﻣ ﻢﻟﺎـﺳ یﺰﯿــﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ ﻒﻠﺘﺨﻣ ﯽﺣاﻮﻧ رد .دﻮﺷ
ﯽﺳرﺮﺑ شور ﺎـﺑ ﺲــﻨﺟ ود ﺮﻫ زا یﺪﻨﻟزﻮﯿﻧ یﺎﻬﺷﻮﮔﺮﺧ ﻪﻌﻟﺎﻄﻣ ﻦﯾا رد شﻮﻬـﯿﺑ زا ﺲـﭘ ﻪـﮐ ﺪـﯾدﺮﮔ بﺎــﺨﺘﻧا مﺮﮔﻮﻠﯿﮐ 2 ﺎﺗ 1/5 نزو ﺮـــﻫ یازا ﻪـﺑ مﺮـﮔﯽـﻠﯿﻣ 90) لﺎـﺘﯿﺑرﺎﺑﻮﺘﻨﭘ ﻢﯾﺪـﺳ ﺎـﺑ نﺪـﺷ ﯽــﺷور ﻖﺑﺎﻄﻣ ﺎﻬﻧآ مﻮﯾدرﺎﮑﯾﺮﭘ و ﻪﻨﯿﺳ ،(نﺪﺑ نزو مﺮﮔﻮﻠﯿﮐ
رﺎــﮐ ﻪﺑ ﺶﻧارﺎﮑﻤﻫ و Paesd Carvallo ﻂﺳﻮﺗ رﺎﺑ ﻦﯿﻟوا ﻪﮐ
رد ﻊﯾﺮـﺳ ﯽـﻠﯿﺧ ﺶـﭙﺗ لﺎــﺣ رد ﺐﻠﻗ و ﻪﺘﻓﺎﮑﺷ (23)دﻮﺑ ﻪﺘﻓر
ﯽﻧﺎـﺳر نﮋﯿـﺴﮐا ،هزﺎــﺗ نﮋﯿﺴﮐا ﻂﺳﻮﺗ ﻪﮐ Tyrode لﻮﻠﺤﻣ
راﺮـﻗ (داﺮـﮔﯽﺘﻧﺎــﺳ ﻪﺟرد 22) قﺎﺗا تراﺮﺣ ﻪﺟرد رد ﺪﺷﯽﻣ .ﺪﺷ هداد ،ﯽــﺑﺮﭼ یﺎﻬــﺘﻓﺎﺑ ندﺮـــﮐ اﺪـﺟ و ﺎﻬـﻧﻮﺧ ﻦﺘـﺴﺷ زا ﺲﭘ ﻪـﺑ ﺖـﺳار ﺰﯿـﻠﻫد ،ﭗـﭼ ﺰﯿـﻠﻫد و ﯽــــﻨﻄﺑ ﻪــﭽﯿﻫﺎﻣ ،یﺪﻧﻮﯿﭘ هدﺮـﮐ زﺎــﺑ صﻮﺼﺨﻣ ﯽﭽﯿﻗ ﺎﺑ ار نآ ﻪﮐ ﺪﻧﺎﻣﯽﻣ ﯽﻗﺎﺑ ﯽﯾﺎﻬﻨﺗ راﺮـﻗ ﻖـﻘﺤﻣ ﺪـﯾد ضﺮـﻌﻣ رد ﺖـﺳار ﺰﯿــﻠﻫد ﯽﻠﺧاد ﺢﻄﺳ ﺎﺗ .دﺮﯿﮔ ﺮﯾز رد ﺖﺳار ﺰﯿﻠﻫد تﺎﻌﻄﻗ مﺎﻤﺗ ﺖﻓاﺮﻇ ﺎﺑ ﻪﻠﺣﺮﻣ ﻦﯾا رد هﺮـﮔ ﻪـﮐ ﯽﻧﺎـﻣز ﺎــﺗ صﻮﺼﺨﻣ ﯽﭽﯿﻗ ﺎﺑ یرﻮﻧ پﻮﮑﺳوﺮﮑﯿﻣ 15×15 دوﺪـﺣ رد یدﺎــﻌﺑا ﺎﺑ نآ فاﺮﻃا و یﺰﯿﻠﻫد ﯽﺳﻮﻨﯿﺳ ﻪـﺑ هﺪـﺷ هدﺎـﻣآ ﺖﻓﺎـﺑ ﺲﭙــﺳ ﺪﺷﯽﻣ اﺪﺟ ﺪﻧﺎﻤﺑ ﯽﻗﺎﺑ ﺮﺘﻤﯿﻠﯿﻣ زا ﺲـﭘ و ﻞـﻘﺘﻨﻣ ﯽﮑﯾﺮﺘــﮑﻟا یﺎﻬﺘﯿﻟﺎﻌﻓ ﺖﺒﺛ ﯽﻣﻮﯿﻨﯿﻣﻮﻟآ ﮏﻗﺎﺗا ﻂــﺳﻮﺗ ﻢـﺋاد رﻮـﻄﺑ یاﻪـﺸﯿﺷ فﺮـﻇ نورد نﺪـﺷ ﺖــــﺑﺎﺛ
.ﺪــﺷﯽﻣ ﯽﻧﺎـﺳر نﮋﯿـﺴﮐا و ﻪـﯾﺬﻐﺗ O2 و Tyrode لﻮـﻠﺤﻣ
ﻪــﯿﻠﺨﺗ ﯽﺻﺎــﺧ ﭗــﻤﭘ ﻂـــﺳﻮﺗ Tyrode لﻮـﻠﺤﻣ ﺲــــﭙﺳ
.ﺪﯾدﺮﮔﯽﻣ یﺰﯿـﻠﻫد ـ ﯽــﺳﻮﻨﯿﺳ هﺮﮔ ﯽــــﮑﯾﺮﺘﮑﻟا یﺎﻬﺘﯿﻟﺎﻌﻓ اﺪﺘﺑا رد ﺖـــﺒﺛ لﺮﺘـﻨﮐ ناﻮـــــﻨﻋ ﻪــﺑ یﺰﮐﺮﻣ و ﯽـــﻄﯿﺤﻣ ﯽﺣاﻮﻧ زا ﻞـﮑﯿﻧ رﻻﻮـﻣوﺮﮑﯿﻣ 40 ضﺮـﻌﻣ رد ﻪــــﻧﻮﻤﻧ ﺪــﻌﺑ و هﺪـــﺷ ﺖــﺒﺛ ﯽــﮑﯾﺮﺘﮑﻟا یﺎﻬـﺘﯿﻟﺎﻌﻓ دﺪـﺠﻣ رﻮـﻄﺑ و ﺖـﻓﺮﮔﯽـﻣ راﺮـﻗ .ﺪﯾدﺮﮔﯽﻣ داﺮــﮔﯽــﺘﻧﺎﺳ ﻪــــﺟرد 32 یﺎـﻣد رد ﺎــــﻬﺸﯾﺎﻣزآ مﺎـﻤﺗ مﺎـــﻤﺗ ﯽــــﮑﯾﺮﺘﮑﻟا ﺖـــــﯿﻟﺎﻌﻓ ﺖــــﺒﺛ .(24)ﺪـــﺷﯽﻣ مﺎـﺠﻧا و هدﻮــﺑ ﯽــــــﻟﻮﻠﺳ ﻞـــــﺧاد ﺖــــــﺒﺛ عﻮـﻧ زا ﺎﻫﻪـــﻧﻮﻤﻧ ترﻮﺻ Conventional glass microelectrode ﻂـــﺳﻮﺗ .ﺖﻓﺮﮔﯽﻣ ﻞـﺻو هﺪــﻨﻨﮐ ﺖﯾﻮﻘﺗ ﺎﯾ ﺮﯾﺎﻓ ﯽﻠﭙﻣآ ﮏﯾ ﻪﺑ ﺎﻫدوﺮﺘﮑﻟاوﺮﮑﯿﻣ .ﺪﻧدﻮﺑ هﺪﺷ هﺪﻫﺎـﺸﻣ ﻞﺑﺎـﻗ ﺎﻬـﯿﺟوﺮﺧ ﺮﺗﻮﯿﭙﻣﺎــﮐ رﻮﺘﯿﻧﺎﻣ ﻪﺤﻔﺻ یور .ﺪﻧﺪﺷﯽﻣ هﺮﯿﺧذ ﺮﺗﻮﯿﭙﻣﺎﮐ رد و هدﻮﺑ
گﻮﻟﺎـﻧآ هﺪــﻨﻨﮐ ﻞــــﯾﺪﺒﺗ ﻪﮐ CED1401 هﺎــﮕﺘﺳد ﮏـــﯾ هﺪـــﺷ هداد راﺮـﻗ ﺮــــﯿﺴﻣ رد ﺰــــﯿﻧ ﺖـــﺳا لﺎـــﺘﯾﮋﯾد ﻪﺑ .دﻮﺑ ﻢـﻠﻗ ﯽﺠﻧﺮﻄـﺷ ﺬﻏﺎـﮐ یور ﯽﮑﯾﺮﺘــﮑﻟا یﺎﻬﺘﯿﻟﺎﻌﻓ ﯽﻓﺮﻃ زا .ﺪﺷﯽﻣ ﺖﺑﺎﺛ ﺰﯿﻧ تﺎﺒﺛ درﻮـﻣ ﺮـﯾز یﺎـﻫرﻮﺘﮐﺎﻓ هﺪـﺷ ﺖـﺒﺛ ﻞـﻤﻋ ﻞﯿــﺴﻧﺎﺘﭘ ﺮﻫ زا :(1 هرﺎﻤﺷ ﻞﮑﺷ)ﺪﻨﺘﻓﺮﮔ راﺮﻗ یﺮﯿﮔهزاﺪﻧا
ﯽــﺳﻮﻨﯿﺳ هﺮﮔ یﺰﮐﺮﻣ ﻪﯿﺣﺎﻧ زا هﺪﺷ ﺖﺒﺛ ﺖﯿﻟﺎﻌﻓ -1 هرﺎﻤﺷ ﺮﯾﻮﺼﺗ
تاﺮﯿـﯿﻐﺗ ﺖﻋﺮـﺳ و (A ﻞـﻨﭘ) ،ﺎـﺸﻏ ﻞﯿـﺴﻧﺎﺘﭘ .هدرﻮـﺨﻧ ﺖــﺳد یﺰﯿﻠﻫد ـ ﻞﯿـﺴﻧﺎﺘﭘ ،(OS)ﻪـﻠﻗ ﻞﯿـﺴﻧﺎﺘﭘ .ﺪﻧاهﺪـﺷ هداد نﺎــﺸﻧ (B ﻞﻨﭘ)ژﺎﺘﻟو یاﻪﻈﺤﻟ ،(PS)یﺮــﮑﯿﻣﺲﯿﭘ ﺐﯿــﺷ ،(APA)ﻞـــﻤﻋ ﻞﯿـﺴﻧﺎﺘﭘ یﺪـﻨﻠﺑ ،(MDP)ﺮـﻌﻗ یاﻪــﻈﺤﻟ تاﺮﯿـﯿﻐﺗ ﺖﻋﺮـﺳ ﻦﯾﺮﺗﻻﺎـﺑ ﺎـﯾ ﯽـﮔﺪﻧورﻻﺎـﺑ ﺖﻋﺮـﺳ ﻢﻤﯾﺰﮐﺎـﻣ و (CL)هرود لﻮﻃ ،(ADP)ﻞﻤﻋ ﻞﯿﺴﻧﺎﺘﭘ ﻦﯿﺑ ﯽﻧﺎﻣز ﻪﻠﺻﺎﻓ (dv/dt)ژﺎﺘﻟو .ﺪﻧاهﺪﺷ هداد نﺎﺸﻧ ﻞﮑﺷ رد (TOP)ﻞﻤﻋ ﻞﯿﺴﻧﺎﺘﭘ عوﺮﺷ ﻞﺤﻣ
رد ،ﺎــــﺸﻏ ﻞـــﯿﺴﻧﺎﺘﭘ رﻮــــﻈﻨﻣ :Overshoot (OS) -1 هﺪﯿﻣﺎــﻧ ﻪـﻠﻗ ﻞﯿـﺴﻧﺎﺘﭘ ﻪـﮐ ﺪــــﺷﺎﺑﯽﻣ ﻞـﻤﻋ ﻞــــﯿﺴﻧﺎﺘﭘ ﻪـﻠﻗ .دﻮﺷﯽﻣ ﻦﯾﺮﺘﺸﯿﺑ :Maximum diastolic potential(MDP) -2 ﺐــﻠﻗ لﻮﺘـــﺳﺎﯾد ﯽـــﻃ رد هﺪـﺷ ﺖـــﺒﺛ ﯽـــﻔﻨﻣ ﻞـــﯿﺴﻧﺎﺘﭘ هﺪـﺷ یراﺬـﮔمﺎـﻧ ﺮـﻌﻗ ﻞــــﯿﺴﻧﺎﺘﭘ ﻪﺻﻼﺧ رﻮﻄﺑ ﻪﮐ ﺪﺷﺎﺑﯽﻣ
.ﺖﺳا ﻊﻤﺟ ﻞﺻﺎﺣ :Action potential amplitude(APA) -3 ﺖـﻣﻼﻋ ﻦــﺘﻓﺮﮔ ﺮـــﻈﻧ رد نوﺪـﺑ MDP و OS یﺎــﻬﻠﯿﺴﻧﺎﺘﭘ .ﺪﺷﺎﺑﯽﻣ ﺎـﻬﻠﯿﺴﻧﺎﺘﭘ ﻞــــــﯿﺴﻧﺎﺘﭘ یﺪــــﻨﻠﺑ مﺎـــــﻧ ﻪــــﺑ ار ﻞــــﯿﺴﻧﺎﺘﭘ ﻦــﯾا .ﻢـﯿﺳﺎﻨﺷﯽﻣ :Maximum upstroke velocity (MUV) -4 ﻖــــﺘﺸﻣ نﺎــــﻤﻫ ﺎـﯾ ﯽـــــﮔﺪﻧورﻻﺎﺑ ﺖـــﻋﺮﺳ ﻢـــﻤﯾﺰﮐﺎﻣ ﺐـﺴﺣ ﺮـــﺑ ﻪــــﮐ ﺖـــــﺳا ﻞـــﻤﻋ ﻞـــﯿﺴﻧﺎﺘﭘ ﯽـــﻃ ژﺎﺘﻟو ﻪـــــــﺒﺳﺎﺤﻣ هﺎـــــﮕﺘﺳد ﻂــــﺳﻮﺗ ﻪــــﯿﻧﺎﺛ ﺮـــﺑ ﺖـــــﻟو .دﻮـــﺷﯽﻣ رد ﺎـــﺸﻏ ﻞــــﯿﺴﻧﺎﺘﭘ :Take-off potential(TOP) -5 هﺮـﮔ ﻞــﻤﻋ ﻞــﯿﺴﻧﺎﺘﭘ ﯽـــﻌﻗاو ﺖـــﯿﻟﺎﻌﻓ ﻪﮐ ﺖــﺳا ﯽـــﯾﺎﺟ ﮏــــﯾﺮﺤﺗ ﻪــــﻧﺎﺘﺳآ نﺎـﻤﻫ ار نآ ناﻮـﺗﯽﻣ و ﺪــــﻫدﯽﻣ خر .ﺪﯿﻣﺎﻧ ﻞـــــــﯿﺴﻧﺎﺘﭘ ﺐــــــﯿﺷ :Pacemaker slope(PS) -6 ﯽـــﻄﺧ زﺎـﻓ سﺎـﺳا ﺮــــﺑ ﻪــﮐ ﺪــــﺷﺎﺑﯽﻣ یﺮﮑﯿﻣ ﺲــــﯿﭘ یﺮـــــﯿﮔهزاﺪﻧا TOP ﺎﺗ MDP زا یﺮـــﮑﯿﻣ ﺲـــﯿﭘ ﻞﯿﺴﻧﺎﺘﭘ .دﻮﺷﯽﻣ ﻞــــﯿﺴﻧﺎﺘﭘ هرود ﮏـــﯾ لﻮـﻃ :Cycle Length(CL) -7 ﻞــﻤﻋ ﻞﯿـﺴﻧﺎﺘﭘ 2 ﻦـــﯿﺑ نﺎـﻣز ﻞــــﻣﺎﺷ ﻪـﮐ ﺖــــﺳا ﻞـﻤﻋ یﺮﯿــﮔهزاﺪـﻧا ﻞـﻤﻋ ﻞﯿـﺴﻧﺎﺘﭘ ود ﺮـﻫ یﺎﻫﻪـﻠﻗ رد و ﺪـﺷﺎﺑﯽﻣ .دﻮﺷﯽﻣ ﻦـــﯿﺑ نﺎـﻣز :Action potential duration(APD) -8 ﺖـﻟوﯽﻠﯿﻣ -30 رد ﻪــﮐ ﺖﺳا نﺪﺷ هﺰﯾرﻻﻮﭘﺮﭙﯿﻫ و هﺰﯾرﻻﻮﭘد .دﻮﺷﯽﻣ یﺮﯿﮔهزاﺪﻧا ﺐــــﺴﺣ ﺮـﺑ یدﻮــــﺨﺑدﻮﺧ ﺖــــﯿﻟﺎﻌﻓ ناﺰﯿـﻣ :Rate -9 .دﻮــﺷﯽﻣ یﺮﯿـﮔهزاﺪـﻧا هﺎﮕﺘـﺳد ﻂـــﺳﻮﺗ و ﺖــــﺳا ﺰـﺗﺮﻫ ﻪـﻧﺎﮔﻪﺳ ﯽﺣاﻮﻧ زا ﮏــﯾ ﺮﻫ (ﺮـــﺘﻤﯿﻠﯿﻣ) ﻪـــﻠﺻﺎﻓ ﻦـــﯿﻨﭽﻤﻫ جاﺮﺨﺘــﺳا ﺰﯿـــﻧ ﺲﯿﻟﺎﻨﯿﻣﺮﺗﺎﺘـﺴﯾﺮﮐ ﺎـﯾ ﯽــــﯾﺎﻬﺘﻧا ﻎــﯿﺘﺳ زا .ﺪﯾدﺮﮔ ﻂــﺳﻮﺗ (SEMs) ﺎﻬــﻨﯿﮕﻧﺎﯿﻣ رﺎـــﯿﻌﻣ یﺎـﻄﺧ و ﻦــﯿﮕﻧﺎﯿﻣ
ﺖــــﺴﺗ و یﺮـــــﯿﮔهزاﺪﻧا EXCELL و CSTAT راﺰﻓامﺮﻧ
ﻪـﺘﻓﺮﮔ رﺎـﮐ ﻪـﺑ ﺎﻬـﺗوﺎﻔﺗ ﯽـــﺳرﺮﺑ رﻮــــﻈﻨﻣ ﻪﺑ T student .ﺪﻧﺪﺷ
ﺞﯾﺎﺘﻧ ﯽــﺣاﻮﻧ زا هﺪـﺷ ﺖـﺒﺛ ﻞـﻤﻋ یﺎﻬﻠﯿـﺴﻧﺎﺘﭘ 2 هرﺎﻤـﺷ ﻞـﮑﺷ فﺮﺼﻣ زا ﻞﺒﻗ ار یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ یﺰﮐﺮﻣ و ﯽﻄﯿﺤﻣ .ﺪﻫدﯽﻣ نﺎﺸﻧ ﻞﮑﯿﻧ
ﻞــــﯿﺴﻧﺎﺘﭘ ﺮـﺑ ﻞـﮑﯿﻧ رﻻﻮــﻣوﺮﮑﯿﻣ 40 ﺮـــﺛا -2 هرﺎﻤﺷ ﺮـــﯾﻮﺼﺗ
یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ یﺰـــﮐﺮﻣ و ﯽـﻄﯿﺤﻣ ﻪـــﯿﺣﺎﻧ یﺎﻬﻟﻮﻠﺳ ﻞــــﻤﻋ رﻮـﻀﺣ رد و لﺮــــﺘﻨﮐ ﻞـﻤﻋ یﺎﻬﻠﯿـﺴﻧﺎﺘﭘ .ﻢـــــﻟﺎﺳ و هدرﻮـــﺨﻧ ﺖﺳد .ﺪﻧاهﺪﺷ هداد نﺎـــﺸﻧ و هﺪـــﯾدﺮﮔ ﻢــﺳر ﻢـــﻫ یور ﺮﺑ ﻞـــﮑﯿﻧ
ﻢـــﻤﯾﺰﮐﺎﻣ (9)ﺪـــﺷ شراﺰــﮔ ﻪـــﺘﺷﺬﮔ رد ﻪﮐ رﻮﻃ نﺎﻤﻫ ﻞﯿــﺴﻧﺎﺘﭘ ،ﻪﻠﻗ ﻞـــﯿﺴﻧﺎﺘﭘ ،ﻞــﻤﻋ ﻞﯿﺴﻧﺎﺘﭘ ﯽﮔﺪﻧورﻻﺎﺑ ﺖﻋﺮﺳ رد هدﻮـــﺑ یﺰﮐﺮﻣ ﻪـــﯿﺣﺎﻧ زا ﺮـﺘﮔرﺰﺑ ﯽﻄﯿﺤﻣ ﻪﯿﺣﺎﻧ رد ﺮﻌﻗ زا ﺮﺘــﮔرﺰﺑ یﺰﮐﺮﻣ ﻪﯿﺣﺎﻧ رد یﺮﮑﯿﻣ ﺲــﯿﭘ ﺐﯿﺷ ﻪــﮐ ﯽﻟﺎﺣ ﺖــﺳد و ﻢﻟﺎـــﺳ یﺰﯿـﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮـﮔ ﯽـﻄﯿﺤﻣ ﻪـﯿﺣﺎﻧ 30 یاﺮـﺑ ﻞـﮑﯿﻧ رﻻﻮـﻣوﺮﮑﯿﻣ 40 ﻪــﮑﻧآ زا ﺲﭘ .ﺖﺳا هدرﻮﺨﻧ 40 هﺪﻣآ ﺖﺳد ﻪﺑ ﺞـــﯾﺎﺘﻧ سﺎﺳا ﺮﺑ ،ﺪﺷ ﻪﺘﻓﺮﮔ رﺎﮐ ﻪﺑ ﻪﻘﯿﻗد تﺎــﺼﺘﺨﻣ ﻞﮑـﺷ ﺮـﺑ یرادﯽـﻨﻌﻣ تاﺮـﺛا ﻞـﮑﯿﻧ رﻻﻮـﻣوﺮﮑﯿﻣ
ﻪــﯿﺣﺎﻧ رد ﻪـﭼ و ﯽـــﻄﯿﺤﻣ ﻪـﯿﺣﺎﻧ رد ﻪـﭼ ﻞـﻤﻋ ﻞــــﯿﺴﻧﺎﺘﭘ ﻢﻟﺎـﺳ و هدرﻮـﺨﻧ ﺖـﺳد یﺰﯿـﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮــﮔ یﺰﮐﺮﻣ ﯽــﮔﺪﻧورﻻﺎﺑ ﺖﻋﺮﺳ ﻢﻤﯾﺰﮐﺎﻣ ﺮﺑ ﯽــــﻤﮐ ﺮﺛا ﻂﻘﻓ .ﺖــــﺷاﺪﻧ رادﯽـﻨﻌﻣ ﺮـﺛا ﻦـﯾا ﻪـﮐ ﺖــﺷاد یﺮﮑﯿﻣﺲﯿﭘ ﻞﻤﻋ ﻞــﯿﺴﻧﺎﺘﭘ و 4 و 3 یﺎﻬﻠﮑـﺷ رد ﻪـﻧﻮﻤﻧ 9 رد رﻮـﮐﺬﻣ تاﺮـﺛا .ﺖــﺳا هدﻮﺒﻧ هﺪﻫﺎـﺸﻣ یرادﯽﻨﻌﻣ تاﺮﯿﯿﻐﺗ ﺎﻬﺘﻟﺎﺣ مﺎﻤﺗ رد .ﺪﻧاهﺪﺷ ﻪﺻﻼﺧ .ﺪﯾدﺮﮕﻧ
رد ﯽﮑﯾﺮﺘــﮑﻟا ﺖﯿﻟﺎﻌﻓ ﺮﺑ ﻞﮑﯿﻧ رﻻﻮﻣوﺮﮑﯿﻣ 40 ﺮﺛا -3 هرﺎﻤﺷ ﺮﯾﻮﺼﺗ
.ﻢﻟﺎﺳ و هدرﻮﺨﻧ ﺖﺳد یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ یﺰﮐﺮﻣ و ﯽﻄﯿﺤﻣ ﯽﺣاﻮﻧ ﻞﯿﺴﻧﺎﺘﭘ (MDP)ﺮﻌﻗ و ،(OS)ﻪﻠﻗ رد ار ﯽﻟﻮﻠﺳ یﺎﺸﻏ ﻞﯿﺴﻧﺎﺘﭘ ﯽﯾﻻﺎﺑ ﻞﻨﭘ APD ﯽﻨﯿﯾﺎـﭘ ﻞﻨــﭘ و MUV ﺎﯾ dv/dt ﯽﻧﺎﯿﻣ یﺎﻫﻞﻨﭘ .ﺪﻫدﯽﻣ نﺎﺸﻧ ﻞﻤﻋ یﺮﯿــــﮔرﺎــﮑﺑ یﺎــﻨﺛا رد (Con=ﯽﻟﺎــﺧ یﺎﻬــﻣاﺮﮔﻮﺘــﺴﯿﻫ) ﻞــﺒﻗ رد ار ﻞــﮑﯿﻧ فﺮــﺼﻣ زا ﺪــﻌﺑ و (هدرﻮــﺧ رﻮــﺷﺎﻫ یﺎﻬـــﻣاﺮﮔﻮﺘـﺴﯿﻫ)ﻞـﮑﯿﻧ یﺎـﻫ هداد ،فاﺮـﮔ ﺮـﻫ رد .ﺪـﻫدﯽﻣ نﺎــﺸﻧ (W.o=ﯽﻟﺎﺧ یﺎﻬﻣاﺮﮔﻮﺘﺴﯿﻫ) ﺖـﺳار فﺮــﻃ رد یﺰﮐﺮﻣ ﻪﯿﺣﺎﻧ یﺎﻫهداد و ﭗﭼ فﺮﻃ رد ﯽﻄﯿﺤﻣ ﻪﯿﺣﺎﻧ .ﺪﻧاهﺪﯾدﺮﮔ ﻢﺳر
رد ﯽﮑﯾﺮﺘــﮑﻟا ﺖﯿﻟﺎﻌﻓ ﺮﺑ ﻞﮑﯿﻧ رﻻﻮﻣوﺮﮑﯿﻣ 40 ﺮﺛا -4 هرﺎﻤﺷ ﺮﯾﻮﺼﺗ
.ﻢﻟﺎﺳ و هدرﻮﺨﻧ ﺖﺳد یﺰﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ یﺰﮐﺮﻣ و ﯽﻄﯿﺤﻣ ﯽﺣاﻮﻧ نﺎـﺸﻧ رد ار (Cycle length)ﻞـﻤﻋ ﻞﯿـﺴﻧﺎﺘﭘ هرود ﮏــﯾ لﻮﻃ ﯽﯾﻻﺎﺑ ﻞﻨﭘ ﻞـﺒﻗ رد ار یﺮـﮑﯿﻣﺲﯿﭘ ﺐﯿـﺷ ﯽﻨﯿﯾﺎـﭘ ﻞــﻨﭘ و Rate ﯽﻧﺎﯿﻣ یﺎﻬﻠﻧ .ﺪﻫدﯽﻣ یﺎﻬـﻣاﺮﮔﻮﺘــﺴﯿﻫ)ﻞﮑﯿﻧ یﺮﯿﮔرﺎﮑﺑ یﺎﻨﺛا رد (Con=ﯽﻟﺎﺧ یﺎﻬﻣاﺮﮔﻮﺘﺴﯿﻫ) (W.o=ﯽﻟﺎـﺧ یﺎﻬـﻣاﺮﮔﻮﺘـﺴﯿﻫ)ﻞـﮑﯿﻧ فﺮــﺼﻣ زا ﺪﻌﺑ و (هدرﻮﺧ رﻮﺷﺎﻫ و ﭗـﭼ فﺮـﻃ رد ﯽـﻄﯿﺤﻣ ﻪـﯿﺣﺎﻧ یﺎــﻫهداد ،فاﺮﮔ ﺮﻫ رد .ﺪﻫدﯽﻣ نﺎﺸﻧ .ﺪﻧاهﺪﯾدﺮﮔ ﻢﺳر ﺖﺳار فﺮﻃ رد یﺰﮐﺮﻣ ﻪﯿﺣﺎﻧ یﺎﻫهداد
ﺚﺤﺑ رد ﯽﻤﯿـﺴﻠﮐ یارﺬـﮔ ﯽــــﻧﻮﯾ نﺎـﯾﺮﺟ ﺶـــــﻘﻧ و ﻢـــﻬﺳ ﺮـــﻈﻧ ﻪـﺑ ﻦـﺌﻤﻄﻣ ﺮﯿـﻏ و کﻮﮑـﺸﻣ ،یﺮـــﮑﯿﻣ ﺲـﯿﭘ ﺖﯿﻟﺎـﻌﻓ .ﺪﺳرﯽﻣ یﺮﺗﻮﯿﭙﻣﺎــﮐ یﺎﻬـــﻟﺪﻣ ﮏــــﯾژﻮﻟﻮﯾﺰﯿـﻓ ﻂــــﯾاﺮﺷ ﺖـﺤﺗ رد یﺮـــــﮑﯿﻣ ﺲـــــﯿﭘ ﺖــــــﯿﻟﺎﻌﻓ ﺎــــﺸﻨﻣ زا ﯽــــﻋﻮﻨﺘﻣ هﺪــــــﺷ شراﺰـــﮔ یﺰـــــــﯿﻠﻫد ـ ﯽـــــﺳﻮﻨﯿﺳ هﺮــــــﮔ .(25-28)ﺖـــﺳا ﯽﻤﯿـﺴﻠﮐ یارﺬـﮔ ﯽـﻧﻮﯾ نﺎـﯾﺮﺟ ،ﺎﻬـﻟﺪﻣ ﻦــﯾا زا ﯽﻀﻌﺑ رد
ﻢـﻫ زﻮـﻨﻫ ﻪـﮐ ﺖـﺳا هﺪـﺷ هداد نﺎـﺸﻧ و هﺪــﺷ ضﺮﻓ ﺐﯾﺎﻏ ﯽﻟﺎـﺣ رد هدﻮـﺑ ﯽــﻨﯿﺑﺶﯿﭘ ﻞــــﺑﺎﻗ یﺮﮑﯿﻣ ﺲـــﯿﭘ ﺖـــﯿﻟﺎﻌﻓ ﻞﯾﺎـﻗ نآ یاﺮـﺑ ﯽــــﺘﯿﻤﻫا ﺎـﺑ ﺶــــﻘﻧ ﺎﻬـﻟﺪﻣ ﯽــﻀﻌﺑ رد ﻪﮐ .ﺪﻧاهﺪﺷ یارﺬـﮔ ﯽـﻧﻮﯾ نﺎـﯾﺮﺟ ندﺮـﮐ دوﺪــﺴﻣ رﻮﮐﺬﻣ یﺎﻬﻟﺪﻣ رد یدﻮــﺨﺑدﻮﺧ ﺖﯿﻟﺎﻌﻓ ناﺰــــﯿﻣ ﺶـــﻫﺎﮐ ﺚـــﻋﺎﺑ ﯽـــﻤﯿﺴﻠﮐ و یﺰـــﮐﺮﻣ یﺎﻬﻟﻮﻠــﺳ رد %26 و 24 ناﺰﯿــﻣ ﻪــﺑ Rate ﺎــﯾ و (30)ﺶﻧارﺎــﮑﻤﻫ و Wilders لﺪـــﻣ رد %9 ،(29)ﯽــــﻄﯿﺤﻣ هﺪــﯾدﺮﮔ شراﺰـــﮔ (31)ﺶــﻧارﺎﮑﻤﻫ و Demir لﺪـﻣ رد %41 .ﺖﺳا ﻪـﮐﻮﻠﺑ ﺮـﺛا ﺮـﺑ ار CL ﺶــــﯾاﺰﻓا (32)ﺶـــﻧارﺎﮑﻤﻫ و Lei
شراﺰـﮔ %5-15 ﻦـﯿﺑ ﻞـﮑﯿﻧ رﻻﻮـﻣوﺮﮑﯿﻣ 40 ﺎـﺑICa T نﺪﺷ
.ﺪﻧاهدﺮﮐ نﺎـﯾﺮﺟ ﻪـﮐ دراد دﻮـﺟو ﻖــــﻓاﻮﺗ ﻦــــﯾا ﯽــــــﻠﮐ رﻮـﻄﺑ ﮏـــــﯾژﻮﻟﻮﯾﺰﯿـــﻓ ﺶــــﻘﻧ ﯽـــــﻤﯿﺴﻠﮐ یارﺬــــﮔ ﯽــــﻧﻮﯾ ﻞــــــﯿﺴﻧﺎﺘﭘ ﺐــــﯿﺷ مود زﺎـﻓ ﺪــﯿﻟﻮﺗ رد ﯽـــﻟﻮﺒﻗ ﻞــــﺑﺎﻗ هﺪــــــﺷ ﻪــﻟوﺰﯾا دﺮـــﻔﻨﻣ یﺎـــﻬﻟﻮﻠﺳ رد یﺮـــﮑﯿﻣ ﺲـــﯿﭘ شﻮــــــﮔﺮـــﺧ ﺐـــﻠﻗ یﺰــــﯿﻠﻫد ـ ﯽــــﺳﻮﻨﯿﺳ هﺮـــﮔ زا .(10)دراد
(22)Zhou و Lipsius ﻦــــــﯿﻨﭽﻤﻫ و (21)Wu و Lipsus رد ﻞـﮑﯿﻧ ﻂــﺳﻮﺗ نآ ندﺮﮐ دوﺪﺴﻣ ﺎﺑ ار رﻮﮐﺬﻣ نﺎﯾﺮﺟ ﺶﻘﻧ شراﺰــﮔ و هدﻮـﻤﻧ ﯽــــﺳرﺮﺑ ﻪـﺑﺮﮔ ﺐــــﻠﻗ ﯽـﮑﺗ یﺎﻬﻟﻮﻠـﺳ ﺶــﻘﻧ ﮏـﯾ ﯽــــﻤﯿﺴﻠﮐ یارﺬـﮔ ﯽــــﻧﻮﯾ نﺎـﯾﺮﺟ ﻪـﮐ ﺪـﻧدﺮﮐ یﺮـﮑﯿﻣ ﺲـﯿﭘ یﺎﻬﻟﻮﻠـﺳ یﺮــﮑﯿﻣ ﺲﯿﭘ ﺖـــﯿﻟﺎﻌﻓ رد ﯽﺳﺎﺳا یزﺎــﺑ (latent pacemaker cells) یﺮﯿﺧﺎـﺗ ﺎـﺑ ﻪــــﯾﻮﻧﺎﺛ .ﺪﻨﮐﯽﻣ ار نآ ﺶـﻘﻧ نﺎــﻘﻘﺤﻣ زا یﺮﮕﯾد هﺪﻋ ﻪﮐ ﺖﺳا ﯽﻟﺎﺣ رد ﻦﯾا ﻪــﯾﻮﻧﺎﺛ و ﯽـﻠﺻا یﺮـﮑﯿﻣ ﺲـﯿﭘ یﺎﻬﻟﻮﻠـﺳ ﻪﺘـﺳد ود ﺮـﻫ رد .(28)ﺪﻨﻧادﯽﻣ نﺎﺴﮑﯾ و ﯽـــﺑﺮﺠﺗ تﺎـﺷراﺰﮔ ﻦـﯾا مﺎـﻤﺗ رد ﻪــــﺟﻮﺗ ﻞﺑﺎـﻗ ﻪـﺘﮑﻧ ﻪـــﺑ طﻮـﺑﺮﻣ ﺞﯾﺎـﺘﻧ ﻪـﮐ ﺖـــﺳا ﻦــــﯾا یﺮﺗﻮﯿﭙﻣﺎـﮐ یﺎﻬـﻟﺪﻣ یﺰﯿـﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮــــﮔ زا هﺪـــــﺷ ﻪـــﻟوﺰﯾا یﺎﻬﻟﻮﻠﺳ هﺮــﮔ زا ﺮﺿﺎــﺣ ﻪـــﻌﻟﺎﻄﻣ رد ﻪـﮐ ﯽﻟﺎـﺣ رد ﺖــــﺳا هدﻮـﺑ
هدﺎﻔﺘـﺳا هدرﻮـﺨﻧ ﺖــﺳد و ﻢـــــﻟﺎﺳ یﺰﯿﻠﻫد ـ ﯽـــﺳﻮﻨﯿﺳ .ﺪﺷ رﻻﻮـــــﻣوﺮﮑﯿﻣ 40 ﻞــــــﮑﯿﻧ زا ﺮـــﺿﺎﺣ ﻪــــﻌﻟﺎﻄﻣ رد یاﺮــﺑ ﯽــــﺻﺎﺼﺘﺧا هﺪــــﻨﻨﮐ دوﺪــــﺴﻣ ناﻮــــﻨﻋ ﻪـﺑ ﻪـﮐ ﺎـﺑ ﺎـﻣا ﺪـــﯾدﺮﮔ هدﺎﻔﺘــﺳا ،دﻮﺑ هﺪـــﺷ شراﺰﮔ نﺎﯾﺮﺟ ﻦـــﯾا زا زود ﻦـــــﯾا ﺮــــﺛا درﻮــــﻣ رد ﻪـﮐ ﯽــــﺗﺎﺷراﺰﮔ دﻮـﺟو ﺐـــــﻠﻗ هﺪـــﺷ ﻪـــﻟوﺰﯾا ﯽـــــﮑﺗ یﺎــــﻬﻟﻮﻠﺳ ﺮـﺑ ﻞــــﮑﯿﻧ 40 ﻪــــــــﮐ ﺪــــــــﯾدﺮﮔ ﻪـــــــــﻈﺣﻼﻣ دراد دﻮـــــــﺟو تﺎـــــﺼﺘﺨﻣ ﺮـــﺑ یرادﯽـﻨﻌﻣ ﺮـﺛا ﻞـﮑﯿﻧ رﻻﻮــــﻣوﺮـــﮑﯿﻣ ﺐﯿــــﺷ ﺎــﯾ یدﻮـــــﺨﺑدﻮﺧ ﺖﯿﻟﺎــﻌﻓ و ﻞـــــﻤﻋ ﻞﯿــﺴﻧﺎﺘﭘ هﺮــﮔ ﯽـــﻄﯿﺤﻣ ﻪـﯿﺣﺎﻧ رد و یﺰـﮐﺮﻣ ﻪـﯿﺣﺎﻧ رد یﺮـﮑﯿﻣﺲﯿﭘ ﻪﺘـﺷاﺪﻧ هدرﻮـﺨﻧ ﺖـــﺳد و ﻢــــﻟﺎﺳ یﺰﯿــﻠﻫد ـ ﯽــﺳﻮﻨﯿﺳ .ﺖﺳا ﺖﯾاﺪﻫ ﺮﯾز تﻻﺎﻤﺘﺣا زا ﯽﮑﯾ ﻪﺑ ار ﺎﻣ ﺖﺳا ﻦﮑﻤﻣ ﺞﯾﺎﺘﻧ ﻦﯾا :ﺪﻨﮐ ﻂﯾاﺮــــﺷ ﺖــﺤﺗ ﻪــﮐ دراد دﻮــﺟو لﺎــﻤﺘﺣا ﻦـــــﯾا -1 ﺖـﺳد یﺰﯿـﻠﻫد ـ ﯽــﺳﻮﻨﯿﺳ هﺮﮔ دﻮﺟو ﺎﺑ ﯽﻨﻌﯾ ﮏﯾژﻮﻟﻮﯾﺰﯿﻓ ﻪـﯿﺣﺎﻧ رد ﻢـﻫ ﯽﻤﯿــﺴﻠﮐ یارﺬﮔ ﯽﻧﻮﯾ نﺎﯾﺮﺟ ﻢﻟﺎﺳ و هدرﻮﺨﻧ لﺎـﻌﻓ ﺮﯿـﻏ ﯽـﺳﻮﻨﯿﺳ هﺮـﮔ ﯽـﻄﯿﺤﻣ ﻪــﯿﺣﺎﻧ رد ﻢﻫ و یﺰﮐﺮﻣ .ﺪﺷﺎﺑ و ﺎـــــﻬﯿﮔﮋـــﯾو زا یداﺪـــــــﻌﺗ ﻪـــــــﮑﻨﯾا ﺢـــــﯿﺿﻮﺗ ﺖــــﺳد یﺰـــــﯿﻠﻫد ـ ﯽــــــﺳﻮﻨﯿﺳ هﺮــــﮔ تﺎـﺻﺎﺼﺘﺧا هﺪـــﺷ ﻪـــﯿﻬﺗ یﺎﻫﻪـــﻧﻮﻤﻧ ﺮــــــﯾﺎﺳ ﺎﺑ ﻢـــﻟﺎﺳ و هدرﻮﺨﻧ زا (small ball tissue) ﯽﺘﻓﺎــﺑ ﮏــﭼﻮﮐ یﺎــــﻬﭘﻮﺗ ﺪــﻨﻧﺎﻣ ﺎـﯾ هﺮــﮔ زا هﺪﺷ ﻪﻟوﺰﯾا یﺎﻬﻟﻮﻠﺳ ،یﺰﯿﻠﻫد ـ ﯽـــﺳﻮﻨﯿﺳ هﺮﮔ رد یﺰﯿـﻠﻫد ـ ﯽــﺳﻮﻨﯿﺳ هﺮﮔ زا ﻞﻤﻋ ﻞﯿﺴﻧﺎﺘﭘ یﺎﻬﺘﯿﻟﺎﻌﻓ ﺖﺒﺛ ﺖـــﺳا هﺪــــﺷ اﺪــﺟ نآ زا یﺰﯿــﻠﻫد ﻪــﭽﯿﻫﺎﻣ ﻪــﮐ ﯽﻟﺎــﺣ (disconnected atrial muscle from sinoatrial node) .ﺪﺷﺎﺑﯽﻣ توﺎﻔﺘﻣ ًﻼﻣﺎﮐ ﻢــــﻟﺎﺳ یﺰـــــﯿﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ رد لﺎـــﺜﻣ رﻮــــﻄﺑ ،ﻞــــﻤﻋ ﻞــــــﯿﺴﻧﺎﺘﭘ ﺖـــــــﯾاﺪﻫ هدرﻮـــــﺨﻧ ﺖـــــﺳد و نﺪـــﺷ ﻪـــﻔﺧ ،ﻞـــﻤﻋ ﻞـــــــﯿﺴﻧﺎﺘﭘ ﺖــﯾاﺪﻫ یﺎﻬﯿﯾﺎــﺳرﺎﻧ ﻪــﭽﯿﻫﺎﻣ ﺮـــﺛا ﺮﺑ یﺰﯿـﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮـﮔ (suppressed) و ﺖــــــﻔﯿﺷ ﺖــــــﯾﺎﻬﻧ رد و نآ فاﺮـــــــﻃا یﺰـــــﯿﻠﻫد ﻪــــــﺠﯿﺘﻧ یﺮــــــﮑﯿﻣ ﺲـــــﯿﭘ ﺖــــــﯿﺻﺎﺧ ﯽــــﯾﺎﺠﺑﺎﺟ
دﻮــــــﺟو و نآ هﺪــــﻧزﺎﺳ یﺎﻬﻟﻮﻠـﺳ توﺎـﻔﺘﻣ ﺖــــــﻌﯿﺒﻃ هﺮــﮔ ﻦــﯿﺑ هﺪـــﻨﻨﮐ هﺰـﯾرﻻﻮﭘﺮـﭙﯿﻫ ﮏــــﯿﻧﻮﺗوﺮﺘﮑﻟا نﺎـﯾﺮﺟ نآ فاﺮــﻃا یﺰﯿـﻠﻫد ﻪـــﭽﯿﻫﺎﻣ و یﺰــــﯿﻠﻫد ـ ﯽــــﺳﻮﻨﯿﺳ .ﺖﺳا یﺰﯿــﻠﻫد ـ ﯽــﺳﻮﻨﯿﺳ هﺮــــــﮔ رد لﺎــــﺜﻣ ناﻮــــﻨﻋ ﻪﺑ یﺎﻬﻟﻮﻠــﺳ رد اﺪﺘﺑا ﻞﻤﻋ ﻞـــﯿﺴﻧﺎﺘﭘ هدرﻮﺨﻧ ﺖﺳد و ﻢـــﻟﺎﺳ ﺖـــﯾاﺪﻫ ﯽـﻄﯿﺤﻣ ﻪـﯿﺣﺎﻧ ﻪـﺑ ﺲﭙـﺳ هﺪــــﺷ دﺎـﺠﯾا یﺰـﮐﺮﻣ .دﻮﺷﯽﻣ ﺎــﯾ یدﻮــﺨﺑدﻮﺧ ،Rate ﺐــﺳﺎﻨﻣ ناﺰــــــﯿﻣ ﻦــــﯾاﺮﺑﺎﻨﺑ یﺰـﮐﺮﻣ ﻪــﯿﺣﺎﻧ یﺮﮑﯿﻣ ﺲﯿﭘ یﺎﻬﻟﻮﻠﺳ ﺖـــﯿﻟﺎﻌﻓ زا ﯽﺳﺎﮑﻌﻧا .ﺖﺳا هﺮــــــﮔ زا یﺰـــــﯿﻠﻫد ﻪــــــﭽﯿﻫﺎﻣ ﻪـــﮐ ﯽــــﻧﺎﻣز ﺎـﻣا زا یﺮـﮑﯿﻣ ﺲـﯿﭘ ﺖﯿﻟﺎـﻌﻓ دﻮـﺷﯽﻣ اﺪـﺟ یﺰﯿــﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ اﺪـﯿﭘ ﺖﻔﯿـﺷ ﯽـﻄﯿﺤﻣ ﻪـﯿﺣﺎﻧ ﻪـﺑ یﺰــــﮐﺮﻣ ﻪــﯿﺣﺎﻧ یﺎﻬﻟﻮﻠﺳ .ﺪﻨﮐﯽﻣ ﻞــﮑﯿﻧ رﻮـﻀﺣ رد ﻪـﮐ دﻮـــــﺷ ﻪـﺘﻔﮔ ﺖــــﺳا ﻦـﮑﻤﻣ -2 ﺖـــــﻔﯿﺷ ﯽـﻄﯿﺤﻣ ﻪـــــﯿﺣﺎﻧ ﻪﺑ یﺮـــﮑﯿﻣ ﺲـــﯿﭘ ﺖـــﯿﻟﺎﻌﻓ زا یاهرﺎــﭘ سﺎـــﺳا ﺮـﺑ ﻪـﮑﯿﺋﺎﺠﻧآ زا و ﺖــــﺳا هدﺮـﮐ اﺪـﯿﭘ ﯽـــﻄﯿﺤﻣ ﻪـــــﯿﺣﺎﻧ رد رﻮـﮐﺬﻣ ﯽــــﻧﻮﯾ نﺎـﯾﺮﺟ تﺎـﺷراﺰﮔ هﺪــــﺷ نﺎﻬـﻨﭘ ﻞــــﮑﯿﻧ ﺮـﺛا ﻦـــــﯾاﺮﺑﺎﻨﺑ دراﺪـــﻧ رﻮـــﻀﺣ .ﺖﺳا ﯽـﻧﻮﯾ یﺎﻬـﻟﺎﻧﺎﮐ ﻪـﮐ ﺖـﺳا ﻦـﺷور ﯽــﺑﻮﺨﺑ ﺐﻠﻄﻣ ﻦﯾا -3 ﺪﯾﺎـﺷ ﻦﯾاﺮﺑﺎـﻨﺑ (27)ﺪـﻨﻨﮐﯽﻣ ﺮﯿـﯿﻐﺗ ﻪــﺘﻓﺎﯾ ﺖﺸﮐ یﺎﻬﻟﻮﻠﺳرد ﻦـﯾا رد ار ناﺮــﮕﯾد ﺎﺑ ﯽــﺳرﺮﺑ ﻦﯾا ﺞﯾﺎﺘﻧ فﻼﺘﺧا ﺖﻠﻋ ناﻮﺘﺑ .ﺖﺴﻧاد ﻪﻨﯿﻣز ﺖـﺳا ﻦـﯾا ﺪــﺷﺎﺑ حﺮﻄﻣ ﺖﺳا ﻦﮑﻤﻣ ﻪﮐ یﺮﮕﯾد لﺎﻤﺘﺣا -4 ﻞـﺣاﺮﻣ رد هﺎﺒﺘـﺷا ﺎـﯾ (contamination) ﯽــﮔدﻮﻟآ ﯽﻋﻮﻧ ﻪﮐ .ﺖﺳا هداد خر رﺎﮐ مﺎﺠﻧا ترﻮـﺻ درﻮـﻣ ﻦـﯾا رد مزﻻ یﺎﻬﯿـﺳرﺮﺑ ﻪــﮑﯿﺋﺎﺠﻧآ زا ﺎﻣا لﺎـﻤﺘﺣا ﻦـﯾا ﺖــﺳا نﺎﻨﯿﻤﻃا درﻮﻣ رﺎﮐ مﺎﺠﻧا ﺖﺤﺻ و ﻪﺘﻓﺮﮔ .ﺪﺷﺎﺑﯽﻣ دودﺮﻣ یﺎـﻫهﺪﻨﻨﮐ دوﺪﺴﻣ ﺮﯾﺎﺳ زا -1 :دﻮﺷﯽﻣ دﺎﻬﻨﺸﯿﭘ نﺎﯾﺎﭘ رد
(33)Ryanodine(32)Amiloride ﻞــﯿﺒﻗ زا ﺮﮕﯾد ﯽﺻﺎﺼﺘﺧا
ﺞـــــﯾﺎﺘﻧ و دﻮــــﺷ هدﺎﻔﺘــﺳا (34)ﮏـــﯿﻧوﺪﯿﺷارآ ﺪـــﯿﺳا و ﻪـﺴﯾﺎﻘﻣ ﯽـﺳرﺮﺑ ﻦـﯾا رد هﺪـﻣآ ﺖــــﺳد ﻪـﺑ ﺞـــﯾﺎﺘﻧ ﺎﺑ ﺎﻬﻧآ .ددﺮﮔ زا ﯽﯾﺎﻫﻪــﻧﻮﻤﻧ رد ﻞـﮑﯿﻧ رﻻﻮـﻣﯽﻠﯿﻣ 40 ﺎـﺑ ﺎﻬـﺸﯾﺎﻣزآ -2 اﺪـﺟ شور و یﺰﯿــﻠﻫد ـ ﯽﺳﻮﻨﯿﺳ هﺮﮔ ﯽﺘﻓﺎﺑ ﮏﭼﻮﮐ یﺎﻬﭘﻮﺗ راﺮـﮑﺗ یﺰﯿـﻠﻫد ـ ﯽـﺳﻮﻨﯿﺳ هﺮـﮔ زا یﺰﯿــﻠﻫد ﻪﭽﯿﻫﺎﻣ ندﺮﮐ .ددﺮﮔ ﺮﮑﺸﺗ و ﺮﯾﺪﻘﺗ مﺎــﻤﺗ زا ﺪــــــﻨﻧادﯽﻣ مزﻻ دﻮـﺧ ﺮـﺑ ﻪـﻟﺎﻘﻣ نﺎـﮔﺪﻨـﺴﯾﻮﻧ زﺪــــﯿﻟ هﺎــــﮕﺸﻧاد یژﻮـــــﻟﻮﯾﺰﯿﻓ نﺎـــــﻤﺗرﺎﭘد نﺎــﻨﮐرﺎﮐ ﺎﻬﻟوﺪﺟ و ﺎﻬﺴﮑﻋ ﻪﯿﻬﺗ رد ﻪﮐ ﻪﻧﺎﺧ سﺎﮑﻋ نﺎﻨﮐرﺎﮐ صﻮﺼﺨﺑ زﺎﻨﻬــﺷ ﻢﻧﺎـﺧ مﺮﺘـﺤﻣ رﺎـﮑﻤﻫ زا ﻦـﯿﻨﭽﻤﻫ ﺪﻨﺘـﺷاد یرﺎـﮑﻤﻫ یراﺰﮕﺳﺎﭙﺳ ﺪﻧاهدﺮﮐ یرﺎﯾ ار ﺎﻣ ﻪﻟﺎﻘﻣ ﭗﯾﺎﺗ رد ﻪﮐ ﯽﺿوﺮﻌﻣ .ﺪﻨﯾﺎﻤﻧ
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THE EFFECT OF Ni+2 ON BLOCKING OF THE TRANSIENT Ca+2 CURRENT, (Ica, T) IN THE INTACT SINO-ATRIAL NODE OF THE HEART RABBIT
I II
*M.R. Nikmaram, Ph.D R.M. Boyett, Ph.D
ABSTRACT
The mammalian sino-atrial node is not a uniform tissue in histological and electrophysiological terms.
The differences in ionic currents underlying the regional differences in electrial activity are only just beginning to be understood. One of the ionic currents it is thought to play a role in the center of sino-atrial node for action potential upstroke should be transient Ca+2 current (ICa,T). This prediction was tested in the present study by investigating the effects of block of this current on pacemaker activity in the periphery and center of the nine intact sino-atrial node of the heart rabbit by 40 µM Ni+2 for 30 min. In all cases Ni+2 failed to change significantly action potential configuration either in the center or in the periphery of the intact sino-atrial node. It is possible that under physiological conditions ICa,T is inactive in both the center and peripheral zones of the sino-atrial node of rabbit. Alternatively it is possible that ICa,T is important in the center and pacemaker shift in the present of Ni+2 conceals the effect.
Key Words: 1) Sino-atrial node 2) Transient Ca2+ current(ICa,T) 3) Nickle
I) Assistant professor of physiology, school of rehabilitation, shahnazari Ave, Madar sq., Iran University of Medical Sciences and Health Services, Tehran, Iran(*Correponding author).
II) Professor of physiology, Department of physiology, Leeds University, U.K.
