Induction of pituitary adenylate cyclase-activating polypeptide mRNA in the medial parvocellular part of the paraventricular nucleus of rats following kainic-acid-induced seizure.
We examined the effects of kainic acid (KA)-induced seizure on the expression of the pituitary adenylate cyclase-activating polypeptide (PACAP) gene in the paraventricular nucleus (PVN) of rats using in situ hybridization histochemistry. Subcutaneous administration of KA (12 mg/kg) in adult male Sprague-Dawley rats caused a progressive development of seizure behavior. An induction of the PACAP gene expression in the medial parvocellular part of the PVN (mpPVN) was observed 3, 6, 12, 24 and 48 h after subcutaneous administration of KA. From a nearly undetectable level, PACAP gene expression increased in the mpPVN and reached maximum 12 h after subcutaneous administration of KA. PACAP gene expression returned to near basal level 48 h after stimulation with KA. Using a specific monoclonal PACAP antibody, PACAP immunoreactivity (-IR) gradually increased during the following 24 h after KA administration. In controls, PACAP-IR was located exclusively in nerve fibers of the mpPVN, whereas KA administration induced PACAP-IR in cell bodies of the mpPVN, and a dense accumulation of PACAP-IR nerve fibers in the external zone of the median eminence was observed. Induction of the PACAP gene expression following KA-induced seizure was significantly reduced by pretreatment with diazepam or MK-801 (nonselective N-methly-D-aspartate receptor antagonist). These results suggest that PACAP in the hypothalamo-adenohypophysial system may have a hypophysiotropic role during KA-induced seizure.
Nomura
M
M
Department of Clinical Biochemistry, Bispebjerg Hospital, University of Copenhagen, Denmark.
Ueta
Y
Y
Hannibal
J
J
Serino
R
R
Yamamoto
Y
Y
Shibuya
I
I
Matsumoto
T
T
Yamashita
H
H
D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D007150:Immunohistochemistry; D007608:Kainic Acid; D008297:Male; D009479:Neuropeptides / Q000235:genetics*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism* / Q000503:physiopathology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012640:Seizures / Q000139:chemically induced* / Q000235:genetics / Q000378:metabolism*
C495403:Adcyap1 protein, rat; D000927:Anticonvulsants; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D016291:Dizocilpine Maleate; D003975:Diazepam; D007608:Kainic Acid