A molecular study of hippocampus in dogs with convulsion during canine distemper virus encephalitis.
In this study, we have investigated the expression of the nuclear transcription factor (c-Fos, NFkB), growth factors (nerve growth factor--NGF, brain-derived neurotrophic factor--BDNF), peptides (enkephalin, galanin) and glutamate transporter (AA 504-523 rat EAAC1) in 6 dogs sacrificed immediately after seizure attack during encephalomyelitis due to canine distemper virus (CDV) (as assessed by clinical examination, RT-PCR and viral RNA detection either in blood or brain tissue and CDV immunohistochemistry in brain slices). In all these CDV affected dogs, the observed neurological signs included untreatable seizures, leading to cluster seizure activity and status epilepticus. In the inter-ictal phase abnormal mentation, postural and gait deficits and sometimes involuntary movements such as myoclonus were recorded. The same investigation was carried out in 5 control dogs affected by different disorders, all characterized by the absence of seizures. Brains were dissected out immediately after euthanasia and fixed; sections collected from the dorsal hippocampus were processed for immunohistochemistry. By comparing hippocampus sections obtained from dog with and without seizure, the following regulations were observed. A strong up-regulation of glutamate transporter throughout the cell layers was found together with the onset of nuclear Fos and NFkB-IR in the pyramidal cell layer X. Among the investigated peptides, we observed a slight increase in enkephalinergic fibers and a strong up-regulation of mu-opioid receptors, whereas galanin-IR seemed to be weaker. Finally, both NGF and BDNF expression was strongly up-regulated. BDNF-IR was mainly localized in the apical dendrite in pyramidal neurons. To our knowledge, these data offer the first indication that molecular events described in experimental kindling also occur during spontaneous pathology in animal species sharing close similarities to human neuropathology.
D'Intino
Giulia
G
Department of Veterinary Morphophysiology and Animal Production, DIMORFIPA, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, Bologna, Italy.
Vaccari
Francesca
F
Sivilia
Sandra
S
Scagliarini
Alessandra
A
Gandini
Gualtiero
G
Giardino
Luciana
L
Calzà
Laura
L
D027322:Amino Acid Transport System X-AG / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D004216:Distemper / Q000473:pathology*; D004217:Distemper Virus, Canine; D004285:Dogs; D018792:Encephalitis, Viral / Q000378:metabolism / Q000473:pathology*; D005260:Female; D016762:Genes, fos / Q000235:genetics; D006133:Growth Substances / Q000096:biosynthesis / Q000235:genetics; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology*; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics; D009479:Neuropeptides / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012640:Seizures / Q000378:metabolism / Q000473:pathology*; D013226:Status Epilepticus / Q000209:etiology / Q000473:pathology
D027322:Amino Acid Transport System X-AG; D006133:Growth Substances; D016328:NF-kappa B; D009479:Neuropeptides