title: Regional brain c-fos activation associated with penile erection and other symptoms induced by the spider toxin Tx2-6.
abstract: Brain areas expressing c-fos messenger RNA were mapped by quantitative in situ hybridization after 1-2 h of intoxication with 10 μg/kg Tx2-6, a toxin obtained from the venom of the spider Phoneutria nigriventer. Relative to saline-treated controls, brains from toxin-treated animals showed pronounced c-fos activation in many brain areas, including the supraoptic nucleus, the paraventricular nucleus of the hypothalamus, the motor nucleus of the vagus, area postrema, paraventricular and paratenial nuclei of the thalamus, locus coeruleus, central amydaloid nucleus and the bed nucleus of the stria terminalis. The paraventricular hypothalamus and the bed nucleus of the stria terminalis have been implicated in erectile function in other studies. A possible role for central NO is considered. Acute stress also activates many brain areas activated by Tx2-6 as well as with NOstimulated Fos transcription. Brain areas that appear to be selectively activated by Tx2-6, include the paratenial and paraventricular thalamic nuclei, the bed nucleus of the stria terminalis and the area postrema and the dorsal motor n. of vagus in the medulla. However, direct injections of different doses of the toxin into the paraventricular hypothalamic n. failed to induce penile erection, arguing against CNS involvement in this particular effect.
authors.affiliation: Laboratory of Pharmacology, Instituto Butantan, São Paulo, Brazil. ltroncone@butantan.gov.br
authors.forename: Lanfranco R P
authors.initials: LR
authors.lastname: Troncone
authors.forename: Katherine G
authors.initials: KG
authors.lastname: Ravelli
authors.forename: Fabio C
authors.initials: FC
authors.lastname: Magnoli
authors.forename: Ivo
authors.initials: I
authors.lastname: Lebrun
authors.forename: Debora C
authors.initials: DC
authors.lastname: Hipolide
authors.forename: Roger
authors.initials: R
authors.lastname: Raymond
authors.forename: José N
authors.initials: JN
authors.lastname: Nobrega
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D002491:Central Nervous System Agents / Q000008:administration & dosage / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D017403:In Situ Hybridization; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D009419:Nerve Tissue Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009498:Neurotoxins / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D009928:Organ Specificity; D010410:Penile Erection / Q000187:drug effects*; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D016760:Proto-Oncogene Proteins c-fos / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D062687:Sodium Channel Agonists; D001098:Spider Bites / Q000378:metabolism / Q000473:pathology; D013111:Spider Venoms / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*
chemical_list: D060829:Arthropod Proteins; D015415:Biomarkers; D002491:Central Nervous System Agents; D009419:Nerve Tissue Proteins; D009498:Neurotoxins; D010455:Peptides; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D062687:Sodium Channel Agonists; D013111:Spider Venoms; C540367:Tx2-6 protein, Phoneutria nigriventer