Spektralne i fraktalne karakteristike električne aktivnosti mozga pacova pod akutnim uticajem etarskog ulja kamforovog drveta

Abstract

Odlučili smo se za istraživanje pojave epileptičnih napada kod pacova, izazvanih etarskim uljem kamforovog drveta ili njegovim glavnim konstituentom 1,8-sineolom. Eksperimenti su izvedeni na odraslim pacovima muškog pola Wistar soja. Operativni zahvati i akutna registrovanja elektrofizioloških signala su obavljeni pod Nembutal anestezijom. Registrovani su lokalni potencijali polja kore velikog i malog mozga u uslovima pre i 1 h posle intraperitonealne (i.p.) administracije etarskog ulja kamforovog drveta ili 1,8-sineola. Pacovima je intraperitonealno ubrizgavano etarsko ulje kamforovog drveta (150-750 μl/kg t.m., u 1 ml fiziološkog rastvora i.p.) ili 1,8-sineol (300-500 μl/kg t.m., u 1 ml fiziološkog rastvora, i.p.). Digitalizovani elektrokortikalni signali (frekvence semplovanja: 256 Hz) su analizirani uz pomoć brze Furijeove transformacije, a potom je izračunavana vrednost fraktalne dimenzije (FD) i Hurstovog eksponenta (H). Etarsko ulje kamforovog drveta (≥450 μl/kg t.m.) ili 1,8-sineol (≥300 μl/kg t.m.) indukuju epileptičnu aktivnost sa pojavom pojedinačnih i grupnih šiljaka velike amplitude u elektrokortikogramu sa povremenim kloničnim konvulzijama ekstremiteta, 3-15 minuta nakon administracije supstanci. Na velikom mozgu, nakon administracije etarskog ulja kamforovog drveta, kao i 1,8-sineola, u epohama sa epileptičnom aktivnošću, bio je prisutan veliki porast ukupne snage kao i povećanje relativne snage u delta (0,1-4,0 Hz) frekventnom opsegu, odnosno smanjenje relativne snage u teta (4,1-8,0 Hz), alfa (8,1-15,0 Hz), beta (15,1- 32,0 Hz) i gama (32,1-128,0 Hz) frekventnim opsezima. Potvrđeno je dominantno učešće delta (0,1-4,0 Hz) frekventnog opsega a vrednost relativne snage se kretala od 47 do 87 %. Na malom mozgu, u epohama sa epileptičnom aktivnošću, relativne snage frekventnih opsega su se različito ponašale u odnosu na veliki mozak i različito nakon administracije 1,8-sineola u odnosu na etarsko ulje kamforovog drveta. Razlike između velikog i malog mozga, kao i razlike u delovanju etarskog ulja kamforovog drveta i 1,8-sineola, bile su izraženije u parametrima fraktalne analize. Na velikom mozgu pacova, nakon administracije etarskog ulja kamforovog drveta, u epohama sa epileptičnom aktivnošću, postoji povećanje vrednosti FD u odnosu na kontrolu, a na malom mozgu smanjenje. Suprotno, nakon administracije 1,8-sineola postoji smanjenje vrednosti FD na velikom, odnosno povećanje na malom mozgu. Postojala je i dozna zavisnost odgovora nakon administracije etarskog ulja kamforovog drveta, odnosno 1,8-sineola. Na velikom mozgu, povećanje doze etarskog ulja kamforovog drveta, odnosno 1,8-sineola, u epohama sa epileptičnom aktivnošću, praćeno je povećanjem relativne snage delta (0,1-4,0 Hz) frekventnog opsega, odnosno smanjenjem relativne snage teta (4,1-8,0 Hz), alfa (8,1-15,0 Hz), beta (15,1-32,0 Hz) i gama (32,1-128,0 Hz) frekventnih opsega. Suprotno, na malom mozgu, povećanje doze etarskog ulja kamforovog drveta u epohama sa epileptičnom aktivnošću, praćeno je smanjenjem relativne snage delta (0,1-4,0 Hz), odnosno povećanjem relativne snage teta (4,1-8,0 Hz), alfa (8,1-15,0 Hz) i beta (15,1-32,0 Hz) frekventnih opsega. Na malom mozgu, povećanje doze 1,8-sineola u epohama sa epileptičnom aktivnošću, praćeno je povećanjem relativne snage teta (4,1-8,0 Hz), odnosno smanjenjem relativne snage gama (32,1-128,0 Hz) frekventnog opsega. I na velikom i na malom mozgu pacova, promene vrednosti FD negativno su korelisane sa povećanjem doze kako etarskog ulja kamforovog drveta tako i 1,8-sineola...

We investigated the rat brain activity in acute seizures evoked by camphor tree essential oil or its main constituent 1,8-cineole. The experiments were performed on adult male Wistar rats. The surgery and acute electrophysiological recordings were performed under pentobarbital sodium anesthesia. Local field potentials of cerebral and cerebellar parietal cortex were recorded before and 1 h after intraperitoneal (i.p.) camphor essential oil or 1,8-cineole administration. The rats were intraperitoneally injected with camphor essential oil (150-750 μl/kg b.w., in 1 ml of saline, i.p.) or 1,8-cineole (300-500 μl/kg b.w., in 1 ml of saline, i.p.). The digitized electrocortical signals (sampling frequency: 256 Hz) were analyzed by the Fast Fourier Transform, and were calculated Fractal dimension (FD) and Hurst exponent (H) also. Camphor essential oil (≥450 μl/kg b.w.) and 1,8-cineole (≥300 μl/kg b.w.) induced seizure-like activity with single and multiple spiking of high amplitudes in the parietal electrocorticogram and occasional clonic limb convulsions, 3-15 min after their administration. On the cerebrum, after camphor essential oil and 1,8-cineole administration, in epochs with epileptic activity, there was high increase in total power and an increase in relative power in delta (0,1-4,0 Hz) frequency range, as well as a decrease in relative power in theta (4,1-8,0 Hz), alpha (8,1-15,0 Hz), beta (15,1-32,0 Hz) and gamma (32,1-128,0 Hz) frequency ranges. It was confirmed the dominant presence of the delta (0,1- 4,0 Hz) frequency range and the values of the relative power ranged from 47 to 87 %. On the cerebellum, in epochs with epileptic activity, the relative power of the frequency ranges were behaving differently than cerebrum, as well as after administration of 1,8-cineole compared to the camphor essential oil. The differences between the cerebrum and cerebellum, as well as differences in the activities of the camphor essential oil and 1,8-cineole, were more pronounced in the parameters of fractal analysis. On the cerebrum, after camphor essential oil aministration, in epochs with epileptic activity, there was an increase in the FD value compared to the control, and the decrease on the cerebellum. In contrast, after 1,8-cineole administration there was a decrease in FD value on the cerebrum, and increase on the cerebellum. There was a dose dependence of response after the camphor essential oil and 1,8-cineole administration. On the cerebrum, increasing the dose of the camphor essential oil and 1,8-cineole, in epochs with epileptic activity, correlated with an increase in relative power in delta (0,1 to 4,0 Hz) frequency range and a decrease in relative power in theta (4,1-8,0 Hz), alpha (8,1-15,0 Hz), beta (15,1-32,0 Hz) and gamma (32,1-128,0 Hz) frequency ranges. In contrast, on the cerebellum, increasing the dose of the camphor essential oil in epochs with epileptic activity, correlated with a decrease in relative power in delta (0,1 to 4,0 Hz) and increase in relative power in theta (4,1 to 8,0 Hz), alpha (8,1 to 15,0 Hz) and beta (15,1 to 32,0 Hz) frequency ranges. On the cerebellum, increasing the dose of 1,8-cineole, in epochs with epileptic activity, correlated with an increase in relative power in theta (4,1-8,0 Hz) and a decrease in relative power in gamma (32,1-128,0 Hz) frequency range...