【Animal Modeling】-The inhibitory effect of geraniol on the central nervous system of rats

  Introduction: Geraniol is an important part of essential oils, such as ginger, lemon, lime, lavender, nutmeg, citrus and rose. It is the main acyclic monoterpene in some aromatic herbal oils. It is derived from the Damascus rose of the Mona Lisa and is isolated from Da Fistula, Moldovan Sea Dragon and Holly. Due to its rose-like smell, the substance is widely used in perfumes and toilet liquids. Several studies have reported the effects of geraniol on the central nervous system (CNS) of invertebrates and vertebrates. Geraniol has neuroprotective effects on oxidative stress induced by acrylamide, mitochondrial dysfunction and neurotoxicity.

  In a study, pentanediol pretreatment ameliorated neuromuscular damage, tyrosine hydroxylase expression and α-orthonucleic acid expression in MPTP-toxic Parkinson’s disease mice in a dose-dependent manner. All dyskinesias of animals pretreated with geraniol were improved. Geraniol has antidepressant effects on chronic, unpredictable and mildly stressed mice. Animals treated with geraniol for 3 weeks showed a decrease in depression-related behavior. Geraniol has been further proven to be an anticonvulsant. Studies have found that geraniol prolongs the incubation period of convulsions induced by pentetrazole and protects animals from attack. ent tetrazole is a competitive GABAA receptor antagonist. Many monoterpenoids have inhibitory, calming, hypnotic and anti-anxiety effects. One of the main components of the water extract of peanut stems and leaves is linalool. The extract has sedative and hypnotic effects by affecting the neurotransmitter levels in the brain, brainstem and brain of mice. In pentobarbital-induced sleep tests, isoprene glycol, neoisoamyl glycol, (±)-propylene glycol, (-)-lauryl alcohol, (+)-cis-lauryl alcohol, and (±)-neomenthol It also shows an inhibitory effect. , Showing its calming effect. We believe that geraniol also has an inhibitory effect on the central nervous system. The purpose of this study is to study the effect of geraniol on behaviors related to the power spectrum of the rat cerebral cortex atlas (ECOG). Methods: Wistar rats (3-4 months) were randomly placed in suitable cages and fed with food and water under controlled temperature (22±1°C) and a 12-hour light/dark cycle. Let them accept it freely. The age of the animals (90-120 days) and the choice of route of administration are based on previous behavioral tests and ECOG studies on Wistar rats (with or without pretreatment). Dilute diazepam Z (DZP), thiopental sodium, polyoxyethylene sorbitol monoester (Tween80) and geraniol (98%) with normal saline and inject 1 ml/kg intraperitoneally (I.P.).

  Orifice plate test: The orifice plate installation equipment is a wooden box (66 x 56 x 47 cm) with 16 equidistant holes (diameter 3 cm) on the floor. The animals were randomly divided into the following groups: control group, receiving vehicle (normal saline, n = 7), 25, 50 or 100 mg/kg (n = 15-16) geraniol. Three experimental groups were given; DZP group (0.5 mg/kg, n = 7). After 30 minutes, place each rat in the lower right corner of the opening and record for 5 minutes. The sensor calculates the dive time (number of dives) below the surface of the hole. The parameters evaluated are mileage, fixed time, eating time and diving time. After each test, please carefully clean the floor of the equipment to remove traces of the previous path.

  Field test: The field test consists of a wooden circular instrument painted with black paint (diameter 81 cm, height 65 cm). The rats were randomly divided into 5 groups: SLN (normal saline 0.9%, n = 11), DZP 1.5 mg/kg (anti-anxiety drug positive control, n = 7), DZP 5.0 mg/kg (sedation positive) control, n = 8)), geraniol 25, 50 or 100 mg/kg (n = 6-8). After 30 minutes, each rat was placed in the center of the wilderness by free exploration (5 minutes). We evaluated the travel distance (m), immobility time (s) and the number of hind limbs standing on the field. Barbituric acid-induced sleep time (BIST): Animals were divided into 3 groups: normal saline (n = 12), geraniol 100 mg/kg (n = 12) and DZP 5.0 mg/kg (n = 14) ). After 30 minutes, each rat was injected with thiopental sodium (60 mg/kg) and then placed in a box. For each animal, the disappearance time (latency period) and recovery time (sleep time) of its recovery reflex were evaluated. Surgery: Before surgery, rats were anesthetized by intraperitoneal injection of ketamine (100 mg/kg) and xylazine (10 mg/kg). After confirming the anesthesia conditions, place the animal in a stereotactic frame. A local anesthetic (0.1 ml, 2% lidocaine) was injected percutaneously into the exposed tissues of the head. Use the following positioning coordinates to create three holes from Bregma to embed the electrode group: frontal bone (ap: + 2mm; ml: + 1.5mm), parietal bone (ap: -4.3mm; ml:) -2mm) and occipital bone (ap: -10.1mm; ml: + 1.5mm). Three screws are embedded in the three epidural cortex areas and used as electrodes. They are connected to the pins through a small connector and the data collection line is inserted. The electrode was fixed on the skull with dental acrylic resin, and the animal recovered 5-7 days after the operation.

  Collection and processing of cortical brainwave data: One hour after taking geraniol (100 mg/kg), an electrical cortical (ECOG) record was obtained when the animal was awake. The signal is amplified. The windaq collection system was used for digitization (sampling rate 1000 Hz) and data logging. Before and during the analysis, visually inspect the ECOG records and discard artifacts containing EEG. After recording, divide the original ECOG into 11 intervals. Each interval is 5 minutes. The ECOG power spectrum is analyzed by the Matlab program, and the ECOG power is calculated by the PWELCH function. Obtain the power spectrum digital values of the four main ECoG bandwidths-δ (0.5-4 Hz), θ (4-8 Hz), α (8-13 Hz) and β (13-30 Hz). .. The power of the ECOG wave is expressed as a percentage of the total spectrum power.

  Results: The effect of gelatin on behavior: In the orifice plate test analysis, ANOVA was shown to have significant therapeutic effects on all parameters (distance, fixed time, number of hind limbs standing, head diving). time. Compared with the saline group, the geraniol (100 mg/kg) and DZP0.5 group reduced walking distance. In addition, compared with the normal saline group, animals treated with geraniol had a longer resting time (100 mg/kg). In addition, the administration of geraniol (25 and 50 mg/kg) reduced the fixation time compared to DZP-treated animals. Compared with the normal saline group and DZP 0.5, the animals treated with geraniol (50 and 100 mg/kg) had lower hindlimb standing frequency. Compared with DZP-treated rats, animals that received geraniol (100 mg/kg) had significantly fewer head dives. Compared with normal saline and geraniol, the DZP group (0.5 mg/kg) increased the number of head dives in the 25 mg/kg, 50 mg/kg and 100 mg/kg groups. Compared with the normal saline and diazepa 1.5 mg/kg (DZP1.5) group, the walking distance of the geraniol (25, 50, 100 mg/kg) and DZP (5.0 mg/kg) groups was shortened. .. Compared with the DZP5.0 group, the walking distance of animals treated with geraniol (25 and 50 mg/kg) was also shortened. However, compared with the saline group, the fixation time of the DZP5.0 and geraniol (50 and 100 mg/kg) groups increased. Compared with DZP1.5 and DZP5.0, the fixation time of all animals treated with geraniol was increased. In the number of standing hind limbs, the number in the DZP 5.0 and geraniol (50 and 100 mg/kg) groups decreased, but the number in the DZP 1.5 group was higher than that in the saline group. .. Compared with DZP treatment (1.5 mg/kg), geraniol treatment (25, 50 and 100 mg/kg) and DZP treatment (5.0 mg/kg) reduced the number of hind limbs standing. Compared with the DZP5.0 group, the geraniol-treated rats (25 and 50 mg/kg) had a longer hindlimb standing time. There was no significant difference between barbituric acid-induced sleep time and sleep latency. However, one-way dispersion analysis shows that sleep time has changed. In animals pretreated with DZP 5.0 and geraniol (100 mg/kg), thiopental sodium prolonged sleep time. The effect of geraniol on ECOG power spectrum: Systemic administration of geraniol (100 mg/kg) changed the ECOG power spectrum of rats. Experiments show that in animals treated with geraniol, the δ bandwidth is larger, θ is smaller, and the other bandwidths (α and β) remain unchanged. Conclusion: Geraniol has an inhibitory effect on the central nervous system, can reduce the overall exploration activities of animals, increase the sleep time induced by barbituric acid, and produce slow waves (ultra-slow waves and triangular waves) in rats.