SlideShare une entreprise Scribd logo
1  sur  25
Department of Neuroscience and Pharmacology
Copenhagen, 19th
of June, 2013
Cellular Neuroscience examine
Rune Rasmussen
BSc. Student, Sport and Exercise Sciences
Action potential propagation into the presynaptic
dendrites of rat mitral cells
(Bischofberger and Jonas, 1997)
Mitral cells (MC)
Pre-synaptic neurotransmitter
release to interneurons (glutamate)
Principal projection neurons
Dendrodendritic synapses
contain L- and N-type
Ca2+
channels
Department of Neuroscience and Pharmacology
(Illustration from Neuroscience, fifth edition, 2011)
Mitral cells (MC)
(Illustration from S. Cajal, 1894: La fine structures des centres nerveux)
Department of Neuroscience and Pharmacology
Large soma
Primary dendrite
Aim of study
Department of Neuroscience and Pharmacology
Examine directly the presynaptic voltage signal that
triggers transmitter release at dendrodendritic synapse in MC
Evoked action potential (AP) – fast time course
Whole-cell current-clamp
Somatic current injection
(Illustration from Neuroscience, fifth edition, 2011)
Department of Neuroscience and Pharmacology
Where is the AP initiated?
Evoked AP - fast time course
Department of Neuroscience and Pharmacology
APs initiated near soma
Whole-cell current-clamp
Somatic current injection
Department of Neuroscience and Pharmacology
APs initiated near soma
Whole-cell current-clamp
Dendritic current injection
Department of Neuroscience and Pharmacology
APs amplitude conserved
Amplitude and time course maintained during back-propagation
Which channels mediates this?
Department of Neuroscience and Pharmacology
Voltage-gated Na+
channels present in dendrites
Dendritic outside-out
voltage clamp
(Illustration from Neuroscience, fifth edition, 2011)
Department of Neuroscience and Pharmacology
K+
replaced by Cs+
Department of Neuroscience and Pharmacology
• Fast voltage-dependent activation
• Rapid inactivation
• Sensitive to TTX
Voltage-gated Na+
channels present in dendrites
Na+
channels support AP back-propagation
Somatic current injection
Somatic AP-like voltage command
Current clamp dendrite
Department of Neuroscience and Pharmacology
Small HD, which channels mediates this?
Half-duration (HD)* from
baseline, not lowest
value
½ height
*Half-duration defined in: Nature Reviews Neuroscience 8, 451-465 (June 2007)
Department of Neuroscience and Pharmacology
Fast repolarization phase
Voltage-gated K+
channels present in dendrites
Dendritic outside-out
voltage clamp from -60 to
30 mV
Department of Neuroscience and Pharmacology
Glutathione added
Department of Neuroscience and Pharmacology
• Voltage-dependent activation
• No inactivation
• Sensitive to TEA
Voltage-gated K+
channels present in dendrites
Department of Neuroscience and Pharmacology
K+
channels mediate repolarization phase
Somatic current injection
Somatic AP-like voltage command
Current clamp dendrite
Summary
Amplitude and time course of somatic AP
maintained during AP back-propagation in MC
Voltage-gated Na+
channels support this back-
propagation into MC dendrites
Voltage-gated K+
channels mediate AP
repolarization in MC dendrites
Department of Neuroscience and Pharmacology
Department of Neuroscience and Pharmacology
Copenhagen, 19th
of June, 2013
Cellular Neuroscience examine
Rune Rasmussen
BSc. Student, Sport and Exercise Sciences
Additional diagrams
Department of Neuroscience and Pharmacology
MC filled with biocytinand rhodamine
stained.
Additional diagrams
Department of Neuroscience and Pharmacology
Primary dendrite – Cell attached configuration
Additional diagrams
Department of Neuroscience and Pharmacology
Soma – Before seal formation
Additional diagrams
Department of Neuroscience and Pharmacology
Sodium current vs. distance
Slope = pA/um
Additional diagrams
Department of Neuroscience and Pharmacology
Amplitude of AP
Additional diagrams
Department of Neuroscience and Pharmacology
Potassium current vs. distance
Slope = pA/um
Additional diagrams
Department of Neuroscience and Pharmacology
Half-duration of AP

Contenu connexe

Similaire à Action potential propagation into the presynaptic dendrites of rat mitral cells

Molecular neuropharma
Molecular neuropharmaMolecular neuropharma
Molecular neuropharma
Fred Ecaldre
 
Lidocaine Unmasks L-Type Ca2+ Spikes in the Thalamus
Lidocaine Unmasks L-Type Ca2+ Spikes in the ThalamusLidocaine Unmasks L-Type Ca2+ Spikes in the Thalamus
Lidocaine Unmasks L-Type Ca2+ Spikes in the Thalamus
Igor Putrenko
 

Similaire à Action potential propagation into the presynaptic dendrites of rat mitral cells (20)

Synapse.pptx
Synapse.pptxSynapse.pptx
Synapse.pptx
 
Transcranial Magnetic Stimulation ( TMS) for Chronic Pain
Transcranial Magnetic Stimulation ( TMS) for Chronic PainTranscranial Magnetic Stimulation ( TMS) for Chronic Pain
Transcranial Magnetic Stimulation ( TMS) for Chronic Pain
 
Neuromuscular transmission and its pharmacology
Neuromuscular transmission and its pharmacologyNeuromuscular transmission and its pharmacology
Neuromuscular transmission and its pharmacology
 
Neuromodulation in psychiatry.
Neuromodulation in psychiatry.Neuromodulation in psychiatry.
Neuromodulation in psychiatry.
 
Nerves conduction study
Nerves conduction study Nerves conduction study
Nerves conduction study
 
NuCalm Research
NuCalm Research NuCalm Research
NuCalm Research
 
Electro convulsive therapy
Electro convulsive therapyElectro convulsive therapy
Electro convulsive therapy
 
Molecular neuropharma
Molecular neuropharmaMolecular neuropharma
Molecular neuropharma
 
Primo Vascular/Meridian System 2016
Primo Vascular/Meridian System 2016Primo Vascular/Meridian System 2016
Primo Vascular/Meridian System 2016
 
Hypoxia acute mountain sickness and cerebral edema
Hypoxia acute mountain sickness and cerebral edemaHypoxia acute mountain sickness and cerebral edema
Hypoxia acute mountain sickness and cerebral edema
 
Ncs
NcsNcs
Ncs
 
Lecture7
Lecture7Lecture7
Lecture7
 
Neuron - Overview of Nervous system
Neuron - Overview of Nervous systemNeuron - Overview of Nervous system
Neuron - Overview of Nervous system
 
Unilateral electroconvulsive therapy_in_rabbit_stroke_model1
Unilateral electroconvulsive therapy_in_rabbit_stroke_model1Unilateral electroconvulsive therapy_in_rabbit_stroke_model1
Unilateral electroconvulsive therapy_in_rabbit_stroke_model1
 
Nerve Muscle Physiology
Nerve Muscle PhysiologyNerve Muscle Physiology
Nerve Muscle Physiology
 
Trans cranial magnetic stimulation - Diagnostic & Therapeutic application
Trans cranial magnetic stimulation - Diagnostic & Therapeutic applicationTrans cranial magnetic stimulation - Diagnostic & Therapeutic application
Trans cranial magnetic stimulation - Diagnostic & Therapeutic application
 
lecturei-150109042144-conversion-gate01.pdf
lecturei-150109042144-conversion-gate01.pdflecturei-150109042144-conversion-gate01.pdf
lecturei-150109042144-conversion-gate01.pdf
 
Neuro humoral transmission
Neuro humoral transmissionNeuro humoral transmission
Neuro humoral transmission
 
Lidocaine Unmasks L-Type Ca2+ Spikes in the Thalamus
Lidocaine Unmasks L-Type Ca2+ Spikes in the ThalamusLidocaine Unmasks L-Type Ca2+ Spikes in the Thalamus
Lidocaine Unmasks L-Type Ca2+ Spikes in the Thalamus
 
Exploring ICP, Tissue Oxygenation and RSNA with Implantable Telemetry
Exploring ICP, Tissue Oxygenation and RSNA with Implantable TelemetryExploring ICP, Tissue Oxygenation and RSNA with Implantable Telemetry
Exploring ICP, Tissue Oxygenation and RSNA with Implantable Telemetry
 

Dernier

Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...
Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...
Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...
Sheetaleventcompany
 
Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...
Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...
Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...
dishamehta3332
 
Electrocardiogram (ECG) physiological basis .pdf
Electrocardiogram (ECG) physiological basis .pdfElectrocardiogram (ECG) physiological basis .pdf
Electrocardiogram (ECG) physiological basis .pdf
MedicoseAcademics
 
Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...
Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...
Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...
Sheetaleventcompany
 
Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...
Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...
Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...
Sheetaleventcompany
 
Dehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service Dehradun
Dehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service DehradunDehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service Dehradun
Dehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service Dehradun
Sheetaleventcompany
 

Dernier (20)

Circulatory Shock, types and stages, compensatory mechanisms
Circulatory Shock, types and stages, compensatory mechanismsCirculatory Shock, types and stages, compensatory mechanisms
Circulatory Shock, types and stages, compensatory mechanisms
 
Call Girls Mussoorie Just Call 8854095900 Top Class Call Girl Service Available
Call Girls Mussoorie Just Call 8854095900 Top Class Call Girl Service AvailableCall Girls Mussoorie Just Call 8854095900 Top Class Call Girl Service Available
Call Girls Mussoorie Just Call 8854095900 Top Class Call Girl Service Available
 
Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...
Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...
Nagpur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Nagpur No💰...
 
Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...
Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...
Whitefield { Call Girl in Bangalore ₹7.5k Pick Up & Drop With Cash Payment 63...
 
Electrocardiogram (ECG) physiological basis .pdf
Electrocardiogram (ECG) physiological basis .pdfElectrocardiogram (ECG) physiological basis .pdf
Electrocardiogram (ECG) physiological basis .pdf
 
Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...
Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...
Jaipur Call Girl Service 📞9xx000xx09📞Just Call Divya📲 Call Girl In Jaipur No💰...
 
Call Girls Bangalore - 450+ Call Girl Cash Payment 💯Call Us 🔝 6378878445 🔝 💃 ...
Call Girls Bangalore - 450+ Call Girl Cash Payment 💯Call Us 🔝 6378878445 🔝 💃 ...Call Girls Bangalore - 450+ Call Girl Cash Payment 💯Call Us 🔝 6378878445 🔝 💃 ...
Call Girls Bangalore - 450+ Call Girl Cash Payment 💯Call Us 🔝 6378878445 🔝 💃 ...
 
ANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM.pptx
ANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM.pptxANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM.pptx
ANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM.pptx
 
Chandigarh Call Girls Service ❤️🍑 9809698092 👄🫦Independent Escort Service Cha...
Chandigarh Call Girls Service ❤️🍑 9809698092 👄🫦Independent Escort Service Cha...Chandigarh Call Girls Service ❤️🍑 9809698092 👄🫦Independent Escort Service Cha...
Chandigarh Call Girls Service ❤️🍑 9809698092 👄🫦Independent Escort Service Cha...
 
7 steps How to prevent Thalassemia : Dr Sharda Jain & Vandana Gupta
7 steps How to prevent Thalassemia : Dr Sharda Jain & Vandana Gupta7 steps How to prevent Thalassemia : Dr Sharda Jain & Vandana Gupta
7 steps How to prevent Thalassemia : Dr Sharda Jain & Vandana Gupta
 
Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...
Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...
Premium Call Girls Dehradun {8854095900} ❤️VVIP ANJU Call Girls in Dehradun U...
 
tongue disease lecture Dr Assadawy legacy
tongue disease lecture Dr Assadawy legacytongue disease lecture Dr Assadawy legacy
tongue disease lecture Dr Assadawy legacy
 
Race Course Road } Book Call Girls in Bangalore | Whatsapp No 6378878445 VIP ...
Race Course Road } Book Call Girls in Bangalore | Whatsapp No 6378878445 VIP ...Race Course Road } Book Call Girls in Bangalore | Whatsapp No 6378878445 VIP ...
Race Course Road } Book Call Girls in Bangalore | Whatsapp No 6378878445 VIP ...
 
Call Girls Shahdol Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Shahdol Just Call 8250077686 Top Class Call Girl Service AvailableCall Girls Shahdol Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Shahdol Just Call 8250077686 Top Class Call Girl Service Available
 
Dehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service Dehradun
Dehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service DehradunDehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service Dehradun
Dehradun Call Girl Service ❤️🍑 8854095900 👄🫦Independent Escort Service Dehradun
 
ANATOMY AND PHYSIOLOGY OF REPRODUCTIVE SYSTEM.pptx
ANATOMY AND PHYSIOLOGY OF REPRODUCTIVE SYSTEM.pptxANATOMY AND PHYSIOLOGY OF REPRODUCTIVE SYSTEM.pptx
ANATOMY AND PHYSIOLOGY OF REPRODUCTIVE SYSTEM.pptx
 
Genuine Call Girls Hyderabad 9630942363 Book High Profile Call Girl in Hydera...
Genuine Call Girls Hyderabad 9630942363 Book High Profile Call Girl in Hydera...Genuine Call Girls Hyderabad 9630942363 Book High Profile Call Girl in Hydera...
Genuine Call Girls Hyderabad 9630942363 Book High Profile Call Girl in Hydera...
 
Ahmedabad Call Girls Book Now 9630942363 Top Class Ahmedabad Escort Service A...
Ahmedabad Call Girls Book Now 9630942363 Top Class Ahmedabad Escort Service A...Ahmedabad Call Girls Book Now 9630942363 Top Class Ahmedabad Escort Service A...
Ahmedabad Call Girls Book Now 9630942363 Top Class Ahmedabad Escort Service A...
 
🚺LEELA JOSHI WhatsApp Number +91-9930245274 ✔ Unsatisfied Bhabhi Call Girls T...
🚺LEELA JOSHI WhatsApp Number +91-9930245274 ✔ Unsatisfied Bhabhi Call Girls T...🚺LEELA JOSHI WhatsApp Number +91-9930245274 ✔ Unsatisfied Bhabhi Call Girls T...
🚺LEELA JOSHI WhatsApp Number +91-9930245274 ✔ Unsatisfied Bhabhi Call Girls T...
 
Bandra East [ best call girls in Mumbai Get 50% Off On VIP Escorts Service 90...
Bandra East [ best call girls in Mumbai Get 50% Off On VIP Escorts Service 90...Bandra East [ best call girls in Mumbai Get 50% Off On VIP Escorts Service 90...
Bandra East [ best call girls in Mumbai Get 50% Off On VIP Escorts Service 90...
 

Action potential propagation into the presynaptic dendrites of rat mitral cells

  • 1. Department of Neuroscience and Pharmacology Copenhagen, 19th of June, 2013 Cellular Neuroscience examine Rune Rasmussen BSc. Student, Sport and Exercise Sciences Action potential propagation into the presynaptic dendrites of rat mitral cells (Bischofberger and Jonas, 1997)
  • 2. Mitral cells (MC) Pre-synaptic neurotransmitter release to interneurons (glutamate) Principal projection neurons Dendrodendritic synapses contain L- and N-type Ca2+ channels Department of Neuroscience and Pharmacology (Illustration from Neuroscience, fifth edition, 2011)
  • 3. Mitral cells (MC) (Illustration from S. Cajal, 1894: La fine structures des centres nerveux) Department of Neuroscience and Pharmacology Large soma Primary dendrite
  • 4. Aim of study Department of Neuroscience and Pharmacology Examine directly the presynaptic voltage signal that triggers transmitter release at dendrodendritic synapse in MC
  • 5. Evoked action potential (AP) – fast time course Whole-cell current-clamp Somatic current injection (Illustration from Neuroscience, fifth edition, 2011) Department of Neuroscience and Pharmacology
  • 6. Where is the AP initiated? Evoked AP - fast time course Department of Neuroscience and Pharmacology
  • 7. APs initiated near soma Whole-cell current-clamp Somatic current injection Department of Neuroscience and Pharmacology
  • 8. APs initiated near soma Whole-cell current-clamp Dendritic current injection Department of Neuroscience and Pharmacology
  • 9. APs amplitude conserved Amplitude and time course maintained during back-propagation Which channels mediates this? Department of Neuroscience and Pharmacology
  • 10. Voltage-gated Na+ channels present in dendrites Dendritic outside-out voltage clamp (Illustration from Neuroscience, fifth edition, 2011) Department of Neuroscience and Pharmacology K+ replaced by Cs+
  • 11. Department of Neuroscience and Pharmacology • Fast voltage-dependent activation • Rapid inactivation • Sensitive to TTX Voltage-gated Na+ channels present in dendrites
  • 12. Na+ channels support AP back-propagation Somatic current injection Somatic AP-like voltage command Current clamp dendrite Department of Neuroscience and Pharmacology
  • 13. Small HD, which channels mediates this? Half-duration (HD)* from baseline, not lowest value ½ height *Half-duration defined in: Nature Reviews Neuroscience 8, 451-465 (June 2007) Department of Neuroscience and Pharmacology Fast repolarization phase
  • 14. Voltage-gated K+ channels present in dendrites Dendritic outside-out voltage clamp from -60 to 30 mV Department of Neuroscience and Pharmacology Glutathione added
  • 15. Department of Neuroscience and Pharmacology • Voltage-dependent activation • No inactivation • Sensitive to TEA Voltage-gated K+ channels present in dendrites
  • 16. Department of Neuroscience and Pharmacology K+ channels mediate repolarization phase Somatic current injection Somatic AP-like voltage command Current clamp dendrite
  • 17. Summary Amplitude and time course of somatic AP maintained during AP back-propagation in MC Voltage-gated Na+ channels support this back- propagation into MC dendrites Voltage-gated K+ channels mediate AP repolarization in MC dendrites Department of Neuroscience and Pharmacology
  • 18. Department of Neuroscience and Pharmacology Copenhagen, 19th of June, 2013 Cellular Neuroscience examine Rune Rasmussen BSc. Student, Sport and Exercise Sciences
  • 19. Additional diagrams Department of Neuroscience and Pharmacology MC filled with biocytinand rhodamine stained.
  • 20. Additional diagrams Department of Neuroscience and Pharmacology Primary dendrite – Cell attached configuration
  • 21. Additional diagrams Department of Neuroscience and Pharmacology Soma – Before seal formation
  • 22. Additional diagrams Department of Neuroscience and Pharmacology Sodium current vs. distance Slope = pA/um
  • 23. Additional diagrams Department of Neuroscience and Pharmacology Amplitude of AP
  • 24. Additional diagrams Department of Neuroscience and Pharmacology Potassium current vs. distance Slope = pA/um
  • 25. Additional diagrams Department of Neuroscience and Pharmacology Half-duration of AP

Notes de l'éditeur

  1. Part of the olfactory system. Located in olfactory bulb. Principal projection neurons to other brain regions. Dendrodendritic synapses – dendrites able to release neurotransmitter like axonal terminals.
  2. Part of the olfactory system. Located in olfactory bulb. Principal projection neurons to other brain regions. Dendrodendritic synapses – dendrites able to release neurotransmitter like axonal terminals.
  3. Part of the olfactory system. Located in olfactory bulb. Principal projection neurons to other brain regions. Dendrodendritic synapses – dendrites able to release neurotransmitter like axonal terminals.
  4. Whole cell current clamp – measures regional potentials though numerous channels. APs is equal in amplitude and time course in primary dendrite and soma when current injected in soma.
  5. So where is the AP initiated first? In the primary dendrites? The soma? or in the axon initial segment?
  6. Current injected in soma => AP initiated in the soma first.
  7. Current injected in primary dendrite => AP initiated in the soma first. => The AP is initiated close to the soma, most likely initial axonal segment.
  8. As mentioned both the amplitude and time course is conserved with increasing distance away from AP initiation site => Which channels are mediating this back-propagation into the primary dendrite?
  9. Outside-out voltage clamp recording mode. Depolarizing voltage pulses from -90 mV to -10 mV with and without the sodium channel blocker Tetrodotoxin (TTX) Cesium blocks potassium channels
  10. In response to membrane depolarizing step a fast inward current which quickly inactivates and it is sensitive to TTX => Bears all the characteristics for a voltage-gated sodium current. They conclude that there are voltage-gated sodium channels in the primary dendritic membrane of MC.
  11. Is it the voltage-gated sodium channels that mediates the fast back-propagation in MC dendrites? Control situation; current clamp mode and initiates an AP in soma and primary dendrite in equal size. TTX in extracellular solution; Not able to trigger an AP in the soma region so they use an AP-like voltage camp (Voltage clamp mode) and measures the potential at the primary dendrite (current clamp). Rate of rise is decreased as well as the peak amplitude of the AP. => Sodium channels are supporting the AP back-propagation into primary dendrites in MC.
  12. In the control situation we notice a small half-duration of the AP in the primary dendrite. Which channels are mediating this fast repolarization of the membrane?
  13. Outside-out voltage clamp mode from a patch of the dendritic plasma membrane. Apply voltage steps from -60 mV to 30 mV and measures the current in the pipette under native conditions and in the presence of TEA, a potassium channel blocker. Glutathione inactivates voltage-gated sodium channels.
  14. The current-amplitude is voltage-dependent as with increasing depolarizing steps the outward current is increased. No sign of inactivation when the voltage step is maintained. TEA decreases the amplitude of the outward current even if the same voltage steps is applied. They conclude that there are voltage-gated potassium channels in the primary dendritic membrane of MC. Normally the potassium channel activation time-constant is relatively fixed, but in this case they are highly voltage-sensitive, as with increasing depolarization the time-constant for activation decreases, and is only submillisecond at +30 mV => they only have a very small effect on the AP amplitude.
  15. Is the the voltage-gated potassium channels that mediates the repolarization in MC dendrites? Control situation; current clamp mode and initiates an AP in soma and primary dendrite in equal size. TEA in extracellular solution; They use an AP-like voltage camp (Voltage clamp mode) and measures the potential at the primary dendrite (current clamp). The half-duration of the AP is increased. => Potassium channels are mediating the fast repolarization in the primary dendrites of MC.
  16. Sodium currents all the way from soma to distal dendritic site. Perhaps a bit increase in conductance density with increasing distance from soma?! High variability in recordings.
  17. Equal AP amplitude at both soma and dendritc site under control conditions, but TTX decreases the amplitude at dendrites markedly => Sodium channels are supporting the active back-propagation into MC dendrites.
  18. Potassium currents all the way from soma to distal dendritic sites. Perhaps a little bigger conductance density at more distal site than at soma?!
  19. Potassium currents all the way from soma to distal dendritic sites. Perhaps a little bigger conductance density at more distal site than at soma?!