Multiple Gap Junctions on a Single Neuron

The basics of how to develop, test, and use models.
Post Reply
Priti Gupta
Posts: 5
Joined: Mon Jul 02, 2012 5:15 am

Multiple Gap Junctions on a Single Neuron

Post by Priti Gupta »

Hello,

I am trying to connect a Neuron with 2 other neurons by gap junctions using the pointer method but my code doesn't seem to work. Is it possible to have more than 1 Gap Junction on a single neuron? If yes, is there anything in particular regarding distance between the 2 Gap Junctions etc that I need to keep in mind?

Code: Select all

       func lambda(){local i
	if(numarg()==0){
		print "Calculate decay length(um) with"
		print "  Ra(ohm-cm), Rm(ohm-cm^2), diameter(um)"
		return 0
	}
	i=50*sqrt($2*$3/$1)
	return i
}
//-------------------------------------------------------------------------------
// Build up a model with three neurons which own Na and K channels acting as 
// Hodgkin-Huxley model

create neuron[6]
// create standard hh neurons
proc NeuronGeometry(){ local i,dlamda,n
	if(numarg()!=2){
		print "Create neurons with cell length(um),cell diameter(um)"
		return
	}
	// create standard hh neurons
	for(i=0; i<6; i+=1){
		access neuron[i]
		cm = 1
		Ra = 35.4	
		L = $1
		diam = $2
		insert hh	
		ena 		= 50
		ek  		= -77
		gnabar_hh 	= 0.12
		gkbar_hh 	= 0.036
		gl_hh 		= 0.0003
		el_hh  		= -54.3
		dlamda = lambda(Ra,1.0/gl_hh,diam)/50		
		n= L/dlamda	
		n = int(n/2)*2+1
		nseg=n
	}
}

NeuronGeometry(5000,25)


//-------------------------------------------------------------------------------
//construct gap junctions between each neuron pair for 1st oscillator
objref gpre[7],gpost[7]
for(i=0;i<3;i+=1){
	neuron[i] 	gpre[i]  = new Gap(0.999)
	neuron[(i+1)%3] 	gpost[i] = new Gap(0.001)
	setpointer  gpre[i].vnb,  neuron[(i+1)%3].v(0.001)
	setpointer  gpost[i].vnb, neuron[i].v(0.999)
}
//adjust gap junction conductance
proc gap_r(){local i
	if(numarg()!=3){
		print "provide gap_n0-n1 , gap_n1-n2, and gap_n2-n0 value(MOhm)"
		return
	}
	for(i=1;i<=3;i+=1){
		gpre[i-1].r = $i
		gpost[i-1].r= $i
	}
}
   gap_r(0.9524,0.9524,0.9524)
  	
 	
//construct gap junctions between each neuron pair for 1st oscillator over

// create two stimuli objects(for first oscillator, neuron 0, 1 and 2)
 access neuron[0]
objref st[2]
for(i=0;i<2;i+=1){
	st[i]		= new IClamp(0.01)
	  st[i].del	= 0.5
	  st[i].dur 	= 0.05
	
}
proc SetST(){
	if(numarg()==0){
		print "Set stimulator with interval(ms),st[0] amp,st[1]amp"
		return
	}
	st[1].del = 0.5 + $1	st[0].amp=$2	st[1].amp=$3
}

SetST(2,295.5,300)


//construct gap junctions between each neuron pair for 2nd oscillator



	neuron[3]   gpre[3]  = new Gap(0.999)
	neuron[4]   gpost[3] = new Gap(0.001)
	setpointer  gpre[3].vnb,  neuron[4].v(0.001)
	setpointer  gpost[3].vnb, neuron[3].v(0.999)

	neuron[4]   gpre[4]  = new Gap(0.999)
	neuron[5]   gpost[4] = new Gap(0.001)
	setpointer  gpre[4].vnb,  neuron[5].v(0.001)
	setpointer  gpost[4].vnb, neuron[4].v(0.999)

	neuron[5]   gpre[5]  = new Gap(0.999)
	neuron[3]   gpost[5] = new Gap(0.001)
	setpointer  gpre[5].vnb,  neuron[3].v(0.001)
	setpointer  gpost[5].vnb, neuron[5].v(0.999)

//adjust gap junction conductance
proc gap_r2(){local i
	if(numarg()!=3){
		print "provide gap_n6-n4 , gap_n4-n5, and gap_n5-n6 value(MOhm)"
		return
	}
	
		gpre[3].r = $1
		gpost[3].r= $1
		gpre[4].r = $2
		gpost[4].r= $2
		gpre[5].r = $3
		gpost[5].r= $3
		
}

     gap_r2(0.9524,0.9524,0.9524)	
    // gap_r2(.1,.1,.1)	
    //gap_r(.98,.98,.98)
//construct gap junctions between each neuron pair for 2nd oscillator over


// create two stimuli objects(for second oscillator, neuron 3, 4 and 5)
access neuron[3]
objref st2[2]
for(i=0;i<2;i+=1){
	st2[i]		= new IClamp(0.01)
	st2[i].del	= .5
	st2[i].dur 	= 0.05
	
}
proc SetST2(){
	if(numarg()==0){
		print "Set stimulator with interval(ms),st[0] amp,st[1]amp"
		return
	}
	st2[1].del = .5 + $1	st2[0].amp=$2	st2[1].amp=$3
}

SetST2(2,295.5,300)


//Connecting neurons 2 and 3 with gap junction..


      neuron[2] gpre[6]  = new Gap(0.980)
      neuron[3] gpost[6] = new Gap(0.010)
      setpointer gpre[6].vnb, neuron[3].v(0.010)
      setpointer gpost[6].vnb,neuron[2].v(0.980)
      

gpre[6].r=.98
gpost[6].r=.98


dt=0.001
Dt=0.01
vinit = -65
celsius = 25



In my code, there are 2 Neurons that need to have more than one gap junctions Neurons 2 and 3

Regards,
Priti
ted
Site Admin
Posts: 5795
Joined: Wed May 18, 2005 4:50 pm
Location: Yale University School of Medicine
Contact:

Re: Multiple Gap Junctions on a Single Neuron

Post by ted »

Priti Gupta wrote:my code doesn't seem to work.
How do you know? If an error message is generated, what is the error message?
Is it possible to have more than 1 Gap Junction on a single neuron? If yes, is there anything in particular regarding distance between the 2 Gap Junctions etc that I need to keep in mind?
Yes. No.
Post Reply