Effects of DSP4 and dizolcipine on connectivity of solid E19 cortical grafts to ablated SmI region of adult rats; an in vivo electrophysiological study.
The functional connectivity of an embryonic graft implanted into the lesioned somatosensory cortex and the effect of DSP4 (a selective noradrenergic neurotoxin to noradrenergic terminals) and dizolcipine (a non-competitive NMDA receptor antagonist), was studied electrophysiologically. The forepaw representational area of the rat primary somatosensory cortex was lesioned unilaterally and, 3-4 weeks later, tissue from the same region of E19 rat embryos was implanted into the cavity. At 7-9 months later, the rats were anaesthetized and single unit activity was recorded from the grafts in response to contralateral forepaw, ipsilateral hindpaw and contralateral hindpaw stimulation and compared with that obtained in control rats, in rats pretreated with dizolcipine immediately after lesioning and in rats given DSP4 24 h before transplantation. Neurones within the graft were integrated into the host brain and developed a pattern of representation similar to that of intact rats, but with a reduced proportion of neurones exhibiting short-latency response to contralateral forepaw stimulation and an increased proportion responding to stimulation of more than one paw. Pretreatment with dizolcipine did not increase short-latency responses to stimulation of contralateral forepaw stimulation however pretreatment with DSP4 reduced such responses and increased proportion of inhibitory responses. It was concluded that the noradrenergic system plays an important role in establishing host-graft connectivity. The importance of further pharmacological studies on host-graft connectivity and the relation of such connections to neural plasticity were discussed.
Zarei
Mojtaba
M
Institute of Psychiatry, King's College London, Department of Neuroscience, De Crespigny Park, London SE5 8AF, UK. m.zarei@iop.kcl.ac.uk
Stephenson
John D
JD
D018663:Adrenergic Agents / Q000494:pharmacology*; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004558:Electric Stimulation; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D016332:Fetal Tissue Transplantation; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000187:drug effects* / Q000196:embryology / Q000637:transplantation*; D019737:Transplants
D018663:Adrenergic Agents; D001596:Benzylamines; D018691:Excitatory Amino Acid Antagonists; D018696:Neuroprotective Agents; D009498:Neurotoxins; D016291:Dizocilpine Maleate; C012102:DSP 4