Antinociceptivno djelovanje botulinum toksina tipa A ovisno o mjestu primjene u središnjem živčanom sustavu

master's thesis

• Title (english): Antinociceptive action of botulinum toxin type A regarding the place of application in the central nervous system
• Author: Marijana Bunić
• Mentor: Lidija Bach-Rojecky (mentor)
• Committee member: Lidija Bach-Rojecky (predsjednik povjerenstva)
• Committee member: Živka Juričić (član povjerenstva)
• Committee member: Anita Hafner (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of pharmacology); Zagreb
• Defense date and country: 2017-07-13, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract

Botulinum toksin (BT-A) je najpotentniji poznati toksin te istovremeno farmakološki koristan protein koji ima široku kliničku primjenu. Ispitivanja na životinjama te kliničke studije su pokazale dugotrajno antinociceptivno djelovanje BT-A kod nekih kroničnih bolnih stanja, ali mehanizam djelovanja još nije razjašnjen. Dugo vremena se smatralo da se analgetski učinak postiže na perifernoj razini inhibicijom egzocitoze neurotransmitora uključenih u nastajanje bolnog impulsa. No, sve je više dokaza da nakon periferne primjene BT-A ulazi u neuron i putem aksonalnog transporta dolazi do središnjih okončina živaca u dorzalnom rogu kralježnične moždine gdje inhibira egzocitozu neurotransmitora uključenih u prijenos bolne informacije na drugi neuron u osjetnom putu. Međutim, potrebno je istražiti je li ono segmentalno ili BT-A djeluje na perifernu bol i nakon primjene u više regije središnjeg živčanog sustava (supraspinalno). Stoga je cilj ovog rada ispitati antinociceptivan učinak BT-A nakon primjene u moždane komore (i.c.v.) ili cisternu magnu (i.c.) na dva moedla upalne boli. Jedan je periferni formalinski test u pdručju inervacije ishijadičnog živca, dok je drugi orofacijalni formalinski test u području inervacije trigeminalnog živca. Ispitivanje je provedeno na mužjacima štakora soja Wistar, starim 3-4 mjeseca, na Zavodu za farmakologiju Medicinskog fakulteta (u okviru postojećih odobrenih projekata). BT-A (1 i.j./kg) je primijenjen i.c.v. i i.c. kod formalinskog testa na šapi, a kod orofacijalnog testa primijenjen je i.c. Supraspinalno primijenjen BT-A nije smanjio bol u prvoj (akutnoj) niti u drugoj (upalnoj) fazi formalinskog testa na šapi, dok je primijenjen i.c. smanjio bol u drugoj fazi orofacijalnog formalinskog testa. Dobiveni rezultati pokazuju da BT-A primijenjen supraspinalno ne djeluje na bol na periferiji, iako je paralelnim istraživanjima njegove distribucije u regijama mozga nakon i.c.v. ili i.c. primjene pokazano da putuje u nocicepcijske regije mozga (potvrđeno kroz prisutnost pocijepanog supstrata SNAP-25 imunohistokemijskom metodom). Uzimajuću u obzir i rezultate prethodnih istraživanja da BT-A smanjuje bol na periferiji ako se primijeni intrateklano, rezultati ovog diplomskog rada dodatni su dokaz da se antinociceptivno djelovanje BT-A odvija segmentalno na razini kralježnične moždine.

Abstract (english)

Botulinum toxin (BT-A) is the most potent known toxin and at the same time a pharmacologically useful protein that has a wide clinical application. Animal studies and clinical studies have shown long-term antinociceptive activity of BT-A in some chronic pain states, but the mechanism of action has not yet been clarified. For a long time, the analgesic effect was considered to be at the peripheral level by inhibition of the exocytosis of the neurotransmitters involved in nociception. However, a growing number of evidence suggests that after peripheral administration BT-A enters the neuron and through axonal transport comes to the central nerve endings in the dorsal horn of the spinal cord, where he inhibits the exocytosis of the neurotransmitters involved in transferring the painful information to the next neuron in the pain pathway, but it is still necessary to investigate whether this happens segmentally in spinal cord or the antinociceptive mechanism also takes place on supraspinal level. The purpose of this study is to investigate the antinociceptive effect of BT-A after its application in brain chambers or in cisterna magna on two pain models. One of them is formalin-induced pain model that takes place on area innervated by ischiadic nerve, while the other is orofacial formalin-induced pain model conducted on area inervated by trigeminal nerve. This study was performed on male Wistar rats that were 3-4 months old, at Department of Pharmacology of the Faculty of Medicine (as part of current approved projects). In the formalin test on the rat hind-paw BT-A (1 i.j./kg) was administered i.c.v. and i.c. In orofacial test BT-A was applied i.c. The supraspinally applied BT-A neither reduced pain in the first (acute) phase, nor in the second (inflammatory) phase of the formalin test performed on the rats hind-paw, while BT-A applied i.c. reduced pain in the second phase of the orofacial formalin test. The obtained results show that BT-A, when administered supraspinally, does not have analgesic effect on peripheral pain although it travels to the nociceptive regions of the brain which is proved by presence of cleaved substrate, SNAP-25. Taking into account the results of previous researches the results of this study are additional evidence that the antinociceptive activity of BT-A takes place segmentally at the spinal cord level.

• Keywords: botulinum toksin tipa A; bol; središnji živčani sustav
• Keywords (english): botulinum toxin type A; pain; central nervous system
• Language: croatian
• URN:NBN: urn:nbn:hr:163:546813
• Study programme: Title: Pharmacy; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra farmacije (magistar/magistra farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-04-20 13:12:49