Sb. Colling et al., DENDRITIC SHRINKAGE AND DYE-COUPLING BETWEEN RAT HIPPOCAMPAL CA1 PYRAMIDAL CELLS IN THE TETANUS TOXIN MODEL OF EPILEPSY, Brain research, 741(1-2), 1996, pp. 38-43
A small dose of tetanus toxin injected into the rat hippocampus produc
es a chronic model of temporal lobe epilepsy. We have examined whether
morphological changes occur in hippocampal CAI pyramidal cells in thi
s model by using intracellular injections of biocytin. Eight weeks aft
er the injection of tetanus toxin, significantly more 'dye-coupled' ce
lls were found in this group than in the buffer (control) injected gro
up (63% compared with 7%). Half of these coupled cells appeared to be
linked at the soma, and the other half by dendrodendritic contacts. An
alysis of the dendritic trees revealed that the tetanus toxin group sh
owed a decrease in complexity around the proximal to mid-apical dendri
tic regions and around the mid- to distal basal dendritic regions. The
dye-coupling indicates that electrotonic interaction is induced or st
rengthened between hippocampal neurones, possibly as a result of the e
pilepsy-induced dendritic damage.