Motor Incoordination In Mice Research Articles

Modified Atkins Diet Delayed the Onset of Epileptogenesis, Improved Motor Coordination and Enhanced Learning Memory in Mice

Modified Atkins diet is a high fat, moderate protein and carbohydrate diet that has long been used to manage intractable epilepsy in developed countries. However, the use of this diet for same condition is uncommon in most low- and middle-income countries including Nigeria. In a previous research, we formulated modified Atkins diet using cheap and locally-available food materials in Nigeria. This research is thus, aimed at evaluating the effect of the formulated modified Atkins diet on seizure plasticity using the PTZ-induced kindling model of seizure. We also investigated the effect of sub-chronic use (60 days) of the diet on motor coordination using positional sense test and on visual-spatial reference and learning memory using Morris-water maze. The result revealed that the formulated modified Atkins diet significantly (<i>p<0.05</i>) increased seizure plasticity by reducing the severity of seizure as well as delaying the onset of tonic-clonic seizure and death. The diet also enhanced motor coordination, and improved learning memory, but not reference memory in mice. We therefore concluded that the formulated modified Atkins diet may be of benefit in the management of intractable/treatment-resistant epilepsy, especially in patients who are already suffering from amnesia and/or postural instability since the diet was able to offer protection against seizure-induced memory loss and motor-incoordination in mice.

14-3-3γ haploinsufficiency leads to altered dopamine pathway and Parkinson’s disease-like motor incoordination in mice

The 14-3-3 protein family with seven isoforms found in mammals is widely expressed in the brain and plays various roles in cellular processes. Several studies have reported that 14-3-3γ, one of the 14-3-3 protein isoforms, is associated with neurological and psychiatric disorders, but the role of 14-3-3γ in the pathophysiology of brain diseases is unclear. Although studies have been conducted on the relationship between 14-3-3γ protein and Parkinson’s disease (PD), a common neurodegenerative disorder with severe motor symptoms such as bradykinesia and rigidity, a direct connection remains to be elucidated. We recently showed that adult heterozygous 14-3-3γ knockout mice are hyperactive and exhibit anxiety-like behavior. In this study, we further characterized the molecular and behavioral changes in aged 14-3-3γ heterozygous mice to investigate the role of 14-3-3γ in the brain. We observed decreased dopamine levels and altered dopamine metabolism in the brains of these mice, including changes in the phosphorylation of proteins implicated in PD pathology. Furthermore, we confirmed that they displayed PD symptom-like behavioral deficits, such as impaired motor coordination and decreased ability to the nest-building activity. These findings suggest an association between 14-3-3γ dysfunction and PD pathophysiology.

Combined alcohol and cannabinoid exposure leads to synergistic toxicity by affecting cerebellar Purkinje cells.

Combined use of cannabis and alcohol results in greater psychoactive toxicity than either substance alone, but the underlying central mechanisms behind this worsened outcome remain unclear. Here we show that the synergistic effect of Δ9-tetrahydrocannabinol (THC) and ethanol on motor incoordination in mice is achieved by activating presynaptic type 1 cannabinoid receptors (CB1R) and potentiating extrasynaptic glycine receptors (GlyR) within cerebellar Purkinje cells (PCs). The combination of ethanol and THC significantly reduces miniature excitatory postsynaptic current frequency in a CB1R-dependent manner, while increasing the extrasynaptic GlyR-mediated chronic chloride current, both leading to decreased PC activity. Ethanol enhances THC actions by boosting the blood-brain-barrier permeability of THC and enriching THC in the cell membrane. Di-desoxy-THC, a designed compound that specifically disrupts THC-GlyR interaction without affecting the basic functions of CB1R and GlyR, is able to restore PC function and motor coordination in mice. Our findings provide potential therapeutic strategies for overcoming the synergistic toxicity caused by combining cannabis and alcohol use.

Pharmacological and phosphoproteomic approaches to roles of protein kinase C in kappa opioid receptor-mediated effects in mice

Kappa opioid receptor (KOR) agonists possess adverse dysphoric and psychotomimetic effects, thus limiting their applications as non-addictive anti-pruritic and analgesic agents. Here, we showed that protein kinase C (PKC) inhibition preserved the beneficial antinociceptive and antipruritic effects of KOR agonists, but attenuated the adverse condition placed aversion (CPA), sedation, and motor incoordination in mice. Using a large-scale mass spectrometry-based phosphoproteomics of KOR-mediated signaling in the mouse brain, we observed PKC-dependent modulation of G protein-coupled receptor kinases and Wnt pathways at 5 min; stress signaling, cytoskeleton, mTOR signaling and receptor phosphorylation, including cannabinoid receptor CB1 at 30 min. We further demonstrated that inhibition of CB1 attenuated KOR-mediated CPA. Our results demonstrated the feasibility of in vivo biochemical dissection of signaling pathways that lead to side effects.

Amelioration of ischemia-reperfusion induced functional and biochemical deficit in mice by Ocimum kilimandscharicum leaf extract

The genus Ocimum (family Lamiaceae) has been revered for its diverse biological activities. Various species have been used traditionally to treat CNS disorders and are proven to have neuroprotective effect that is often attributed to their significant antioxidant activity. Ocimum kilimandscharicum (Karpoora Thulasi), a prominent member of this genus is reported to have marked antioxidant activity but its neuroprotective potential has not been explored. Thus, present study was designed to evaluate the cerebroprotective effect of O. kilimandscharicum leaf extract (OKLE) in mice against ischemia reperfusion (I-R) induced brain injury. Bilateral common carotid artery occlusion (BCCAO) for 15min followed by 24h reperfusion was used to induce brain damage in Swiss Albino mice. Animals were treated with OKLE (200 and 400mg/kg, po) once daily for 7days after I-R. Morris water maze and elevated plus maze tests were used to assess long and short term memory while neurological severity score was used to determine motor coordination. Histopathological evaluation (TTC staining) along with brain biochemical parameters (TBARS, reduced GSH and SOD activity) were determined to outline neuroprotective mechanism of OKLE. I-R resulted in marked cognitive impairments, motor incoordination in mice, significant brain damage and increased oxidative stress.Treatment with OKLE produced functional recovery in mice which is manifested by improved memory and motor coordination; reduced cerebral infarct size and brain oxidative stress (TBARS levels) and elevated endogenous antioxidants (reduced GSH and SOD activity). In addition, OKLE showed DPPH radical scavenging and reducing power in-vitro. These results show that O. kilimandscharicum mitigated the neurodegenerative changed induced by I-R in mice probably due to its antioxidant activity.

The biphasic effects of centrally and peripherally administered caffeine on ethanol-induced motor incoordination in mice.

The possible biphasic effect of caffeine on acute ethanol-induced motor incoordination by rotorod evaluation was investigated in mice. Caffeine in various doses was administered intracerebroventricularly (i.c.v.) to mice implanted with permanent indwelling stainless steel guide cannulae and intraperitoneally (i.p.) to non-cannulated animals. A motor incoordinating test dose of ethanol, 2 g kg-1, was given i.p. in both cases. Caffeine less than 25 micrograms administered i.c.v., dose-dependently attenuated while 75 micrograms i.c.v. potentiated ethanol (i.p.)-induced motor incoordination. Similarly, caffeine less than 20 mg kg-1 given i.p., dose-dependently attenuated while 62.5 mg kg-1 potentiated ethanol (i.p.)-induced motor incoordination. The data obtained demonstrated that caffeine given either i.c.v. or i.p. exerted biphasic effects on ethanol-induced motor incoordination. The data also suggested that caffeine antagonized ethanol-induced motor micrograms i.c.v.; less than 20 mg kg-1 i.p.) caffeine is well known to display high affinity for adenosine binding sites. Therefore, the present investigation lends further support to our earlier suggestion that adenosine may be involved in the motor impairing effect of ethanol.

The parallel rod floor test: a measure of ataxia in mice

The parallel rod floor test is a new model of ataxia in mice. It allows the simultaneous measurement of ataxia and locomotor activity. This protocol is designed for researchers examining ethanol-induced motor incoordination in mice, but it should be applicable to other sedative/hypnotic drugs and to testing cerebellar mutant mice or mice with engineered genetic defects. This protocol takes 3 d, with the time per day depending on how many animals are tested. The test allows researchers to quantify differences in motor coordination among genotypes of mice that may differ in locomotor activity. Unlike many other methods for assessing incoordination, the parallel rod floor test yields similar patterns of genetic sensitivity across a range of variant forms of the apparatus.

Blockade of adenosine and dopamine receptors inhibits the development of rapid tolerance to ethanol in mice

Several reports have suggested the involvement of brain adenosine and dopamine receptors in different actions produced by ethanol such as motor incoordination or anxiolytic, hypnotic and reinforcing effects. The co-localization and interaction between adenosine and dopamine receptors in different brain regions has also been well documented. However, few studies have demonstrated the involvement of these mechanisms in the tolerance induced by ethanol. The aim of the present study was to evaluate the role of adenosine and dopamine receptors in the development of rapid tolerance to ethanol-induced motor incoordination in mice. In connection with the rota-rod apparatus, the effects of acute administration of the adenosine receptor antagonists caffeine (non-selective), 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, adenosine A1 receptor antagonist) and 4-(2-[7-amino-2-{2-furyl}{1,2,4}triazolo-{2,3-a}{1,3,5}triazin-5-yl-amino]ethyl)phenol (ZM241385, adenosine A2A receptor antagonist), together with R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SCH23390, dopamine D1 receptor antagonist) and sulpiride (dopamine D2 receptor antagonist), alone or in combination with ethanol (2.25 g/kg, i.p.), were studied. Twenty-four hours after, all animals were re-tested on the rota-rod after receiving the same dose of ethanol. The repeated administration of ethanol promoted a significant reduction of motor impairment on day 2 (i.e. rapid tolerance). This effect was blocked by caffeine (3.0-30.0 mg/kg, i.p.), DPCPX (3.0-6.0 mg/kg, i.p.) or SCH23390 (0.01-0.03 mg/kg, s.c.), but not with ZM241385 (0.5-1.0 mg/kg, i.p.) or sulpiride (1.0-3.0 mg/kg, i.p.). Our results suggest that the rapid tolerance to ethanol-induced motor impairment in mice may be modulated by adenosine A1 receptors and dopamine D1 receptors.

Characterization of the parallel rod floor apparatus to test motor incoordination in mice

Impairment of motor coordination, or ataxia, is a prominent effect of alcohol ingestion in humans. To date, many models have been created to examine this phenomenon in animals. Evidence suggests that the tasks thought to measure this behavior in mice actually measure different components of this complex trait. We have characterized the parallel rod floor apparatus to quantify ethanol-induced motor incoordination. Using genetically heterogeneous mice, we evaluated the influence of rod diameter and inter-rod distance on dose-related ethanol-induced motor incoordination to select parameters that optimized testing procedures. We then used the DBA/2J and C57BL/6J inbred strains of mice to examine the effect of 2 g/kg of ethanol, by serially testing mice on two floor types, separated by 1 week. Finally, we tested eight inbred strains of mice on four floor types to examine patterns of strain sensitivity to 2 g/kg of intraperitoneal ethanol and determined the test parameters that maximized strain effect size. Motor incoordination varied depending on the floor type and strain. When data from strain 129S1/SvlmJ were removed from the analyses because of their extreme behavior, the greatest strain effect size was observed on one floor type during the first 10 min of testing after 2 g/kg of intraperitoneal ethanol. These findings suggest that the parallel rod floor apparatus provides a useful means for examining ethanol-induced motor incoordination in mice but that specific testing procedures are important for optimizing detection of motor incoordination and genetic influences.

Rapid tolerance to Δ 9-tetrahydrocannabinol and cross-tolerance between ethanol and Δ 9-tetrahydrocannabinol in mice

Motor incoordination in the rota-rod test was used to assess the development of rapid tolerance to Δ 9-tetrahydrocannabinol and rapid cross-tolerance between ethanol and Δ 9-tetrahydrocannabinol in mice. Further, the influence of the cannabinoid receptor antagonist SR 141716A ( N-(piperidin-1-yl)-5-(4-chlorophenyl)-4-methyl-1 H-pyrazole-3-carboxyamide) on the motor impairment induced by both drugs was examined. Mice were injected on day 1 with equipotent doses of Δ 9-tetrahydrocannabinol (28 mg/kg, i.p.) and ethanol (2.25 g/kg, i.p.) and tested at 30, 60 and 90 min after the injections. On day 2, control groups received ethanol or Δ 9-tetrahydrocannabinol, some groups received the same treatment as the day before, while the remaining groups switched the treatment. All groups were tested to evaluate tolerance. The development of rapid tolerance to Δ 9-tetrahydrocannabinol was observed and pretreatment with ethanol resulted in rapid cross-tolerance to Δ 9-tetrahydrocannabinol. SR 141716A (2 mg/kg, i.p.) failed to block the development of rapid tolerance to both drugs, ethanol and Δ 9-tetrahydrocannabinol. These results suggest that Δ 9-tetrahydrocannabinol, similarly to ethanol, can induce rapid tolerance to motor incoordination in mice. They also support the use of the 2-day protocol as an effective procedure to reduce the length of drug exposure necessary to induce tolerance.

Involvement of the cerebellar adenosine A 1 receptor in cannabinoid-induced motor incoordination in the acute and tolerant state in mice

Cannabinoids are known to impair motor function in humans and laboratory animals. We have demonstrated an accentuation of cannabinoid (CP55,940)-induced motor incoordination in mice by the adenosine A 1 receptor-selective agonist N 6-cyclohexyladenosine (CHA) (4 ng) using an intracerebellar (ICB) microinjection method. This effect was mediated by the A 1 receptor because pre-treatment with ICB 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) (100 ng), an adenosine A 1 receptor selective antagonist, completely abolished the accentuation. Furthermore, ICB pre-treatment with DPCPX (100 ng) before ICB CP55,940 (15 μg) attenuated the motor incoordination suggesting a modulation by an endogenous adenosine A 1 system. ICB microinjection of CHA or DPCPX prior to ICB vehicle had no effect on normal motor coordination. ICB microinjection of dipyridamole (25 μg), an adenosine transport inhibitor, significantly accentuated the motor incoordination by ICB CP55,940 (15 μg), providing further support for the involvement of endogenous adenosine in the action of CP55,940. Tolerance to the motor incoordinating effect of ICB CP55,940 was demonstrated following 3 days of i.p. CP55,940 (0.1, 1 or 2 mg/kg every 12 or 24 h; total of six or three injections, respectively). Interestingly, animals which exhibited tolerance to ICB CP55,940 also demonstrated tolerance to the accentuating effect of ICB CHA suggesting cross-tolerance between adenosine agonists and cannabinoids. Cross-tolerance was also demonstrated following 3 days of i.p. CHA (0.25 or 1 mg/kg every 24 h; total of three injections) as further evidence of the modulatory role of the cerebellar adenosine system in the acute manifestation of CP55,940-induced motor incoordination. The involvement of cerebellar adenosine and the A 1 receptor in cannabinoid actions is circumstantially supported by previous evidence that CB 1 receptors and A 1 receptors are both localized on cerebellar granule cell parallel fiber terminals and basket cell neurons where they serve to inhibit the release of neurotransmitters.

Cannabinoid-induced motor incoordination through the cerebellar CB 1 receptor in mice

Cannabinoids are known to impair motor function in humans and laboratory animals. We have observed dose-dependent motor incoordination in mice evaluated by rotorod following direct intracerebellar (icb) microinjection of synthetic cannabinoid agonists CP55,940 (5–25 μg) and HU-210 (1.56–6.25 μg), through permanently implanted stainless steel guide cannulas. The motor incoordination was marked at 15, 35 and 55 min post-microinjection. The motor incoordination elicited by HU-210 (6.25 μg) and CP55,940 (20 μg) was significantly blocked by the CB 1 receptor-selective antagonist SR141716A (25 μg icb), indicating mediation by a cerebellar CB 1 receptor. Further direct evidence of CB 1 mediation was obtained through a CB 1 receptor antisense/mismatch oligodeoxynucleotide approach (3 μg/12 h; total of six doses). Mice treated with intracerebellar antisense had a significantly diminished motor incoordination response to intracerebellar CP55,940 15 μg compared to mice that received intracerebellar mismatch or no prior treatment. Also, the response to intracerebellar CP55,940 in the CB 1 mismatch-treated mice did not differ from the mice that received only CP55,940. A separate study using a cerebellar tissue punching technique, following intracerebellar [ 3H]-CP55,940 microinjection, confirmed that cannabinoid drug dispersion following microinjections was exclusively confined to the cerebellum. Microinjection of CP55,940 (20 μg) into the hippocampus, an area with a large density of CB 1 receptors, did not impair motor coordination. Taken together, these results indicate that cannabinoid-induced motor impairment occurs by activation of a CB 1 receptor in the cerebellum. The participation of other brain motor areas in cannabinoid-induced motor incoordination will require future study.

Repeat instability and motor incoordination in mice with a targeted expanded CAG repeat in the Sca1 locus.

To elucidate the pathophysiology of spinocerebellar ataxia type 1 (SCA1) and to evaluate repeat length instability in the context of the mouse Sca1 gene, we generated knock-in mice by inserting an expanded tract of 78 CAG repeats into the mouse Sca1 locus. Mice heterozygous for the CAG expansion show intergenerational repeat instability (+2 to -6) at a much higher frequency in maternal transmission than in paternal transmission. The majority of changes transmitted through the female germline were small contractions, as in humans, whereas small expansions occurred more frequently in paternal transmission. The frequency of intergenerational changes was age dependent for both paternal and maternal transmissions. Mice homozygous for mutant ataxin-1 on a C57BL/6J-129/SvEv mixed background performed significantly less well on the rotating rod than did wild-type littermates at 9 months of age, although they were not ataxic by cage behavior. Histological examination of brain tissue from mutant mice up to 18 months of age revealed none of the neuropathological changes observed in other transgenic models overexpressing expanded polyglutamine tracts. These data suggest that, even with 78 glutamines, prolonged exposure to mutant ataxin-1 at endogenous levels is necessary to produce a neurological phenotype reminiscent of human SCA1. Pathogenesis is thus a function of polyglutamine length, protein levels and duration of neuronal exposure to the mutant protein.

Antagonism by intracerebellar Ro15–4513 of acute ethanol-induced motor incoordination in mice

The possible antiethanol effect of intracerebellarly microinjected Ro15–4513 was investigated using motor incoordination as the test response. The results of this study further confirmed reports from this and other laboratories that this partially negative ligand of benzodiazepine selectively attenuated and nearly reversed the motor impairment of acute ethanol. The attenuation observed after microinjections of doses of 0.05, 0.1, and 0.5 ng was significant and dose related. There was no effect on normal coordination when the highest dose, 0.5 ng, was administered followed by saline instead of a test dose of ethanol. When 0.5 ng of Ro15–4513 alone was microinjected into the cerebellum, no significant change in the locomotor activity was observed. Even a 10-fold higher intracerebellar dose (5 ng) of Ro15–4513 administered alone produced no significant changes in locomotor activity. This suggests that attenuation of ethanol-induced motor incoordination was most likely due to the selective antiethanol effect of Ro15–4513 at the dose range used in the present investigation. The antiethanol effect of intracerebellar Ro15–4513 also reaffirmed the well-known belief that the cerebellum is an important brain region for ethanol's motor-impairing effect. The results also indirectly suggest the inhibition of GABA A-gated chloride ion channel activity as the most likely basis of Ro15–4513's antiethanol effect.

Analysis and pharmacotoxicity of feruloyltyramine as a new constituent and p-coumaroyltyramine in Cannabis sativa L.

Feruloyltyramine (FT), a new amide compound, together with p-coumaroyltyramine (p-CT) was isolated and identified in ethanol extract of cannabis seeds. FT and p-CT were also detected in the roots, leaves and resin of Cannabis sativa L. The intracerebroventicular injection of these amides caused hypothermia and motor incoordination in mice, and the maximal effects were caused 160 to 240 min after the injection. Furthermore, p-CT also exhibited cataleptogenic effect in mice, although FT did not show any effect. These results suggest that these amide compounds may be responsible for some pharmatoxicity of marihuana.

Functional correlation between subclasses of brain adenosine receptor affinities and ethanol-induced motor incoordination in mice

To further investigate if the modulation of ethanol-induced motor incoordination is by brain adenosine A1 and/or A2 receptor, adenosine analogs with wide variability in their affinity for A1 and A2 subtypes were administered ICV and their effect on ethanol-induced (IP) motor incoordination was evaluated by rotorod. A dose-dependent marked accentuation of ethanol-induced motor incoordination by adenosine agonists (CHA, NECA, CPA, DCCA) tested, with nearly no effect on normal motor coordination in the absence of ethanol, was observed. There was a positive correlation between A2 affinity, A2/A1 affinity ratio but a negative correlation between A1 affinity and the potency (ED50) of adenosine agonists to accentuate ethanol-induced motor incoordination. However, with the high potency of CHA and NECA, both having significant affinity for A1 and A2 receptors, together with the well known membrane perturbation by ethanol, it seems difficult to rule out until more information becomes available the contribution of A1 receptor activation to adenosine modulation of ethanol-induced motor incoordination. The high density of high affinity A2 (A2a) in the striatum and of A1 in the cerebellum and several brain areas and the known importance of these two brain areas in the motor control, indirectly supports or at least provides a circumstantial evidence for a functional correlation between ethanol-induced motor incoordination and brain adenosine receptors.

Central nervous system effects and behavioral interactions with ethanol of centrally administered dilazep and its metabolites in mice

Dilazep (i.p.), a coronary vasodilator and an uptake inhibitor of adenosine, dose dependently potentiated acute ethanol-induced motor incoordination in mice. In view of peripheral cardiovascular depressive effects of dilazep, the effect of i.c.v. dilazep (25, 50 and 75 μg), and its metabolites, 1,4-bis(3-hydroxypropyl)perhydro-1,4-diazepine (BHPD) (15, 31 and 62 μg) and 1-[3-(3,4,5-trimethoxybenzoyloxy)propyl]perhydro-1,4-diazepine (TBPD) (62 and 125 μg) on ethanol-induced motor incoordination was studied. Dose-related potentiation of ethanol-induced motor incoordination was noted with dilazep and its metabolites. Whereas dilazep (i.p.) produced no apparent central nervous system (CNS) effects, by i.c.v. route, it caused CNS excitation including tonic-clonic seizures. Adenosine uptake inhibition, Ca 2+ entry blockade or direct activation of adenosine receptors was ruled out as the possible mechanism of seizures because dipyridamole, verapamil or N 6-(2-phenylisopropyl)-adenosine (R-PIA) administered i.c.v., while potentiating ethanol (i.p.)-induced motor incoordination did not produce seizures. The CNS excitation was minimal with BHPD and none with TBPD. Theophylline pretreatment partially blocked potentiation of ethanol-induced motor incoordination by dilazep and BHPD and not by TBPD. The data suggest dilazep-induced potentiation of ethanol-induced motor incoordination is partially due to central adenosine receptor mechanism and partly due to other yet unknown mechanism(s) and further supported our earlier reports about adenosine involvement in the CNS effects of ethanol. The data also suggest that dilazep (i.c.v.)-induced seizures are due to mechanism(s) other than adenosine uptake inhibition, Ca 2+ entry blockade or direct adenosine receptor activation.

Effect of chronically administered methylxanthines on ethanol-induced motor incoordination in mice

The effect of chronic (10 days) administration of methylxanthines, caffeine, IBMX and theophylline on acute ethanol- induced motor incoordination has been investigated in the mice. In animals that received caffeine, 45 and 90 mg/kg/24 h, ethanol, 1.5 g/kg, produced motor incoordination significantly greater compared to that in the control groups. Significantly greater ethanol-induced motor incoordination was seen in animals fed IBMX, 30 and 60 mg/kg/24 h, compared to controls. Ethanol- induced increased motor incoordination in caffeine and IBMX-fed animals was also associated with significantly greater 3H-R-PIA binding in whole brains compared to tap water controls indicating an increase in brain adenosine binding sites. However neither motor incoordination nor 3H-R-PIA binding was altered in theophylline 75 and 150 mg/kg/24 h, fed animals. The increased motor incoordination associated with increased adenosine binding sites in the brains of caffeine and IBMX-fed animals suggests an involvement of central adenosine mechanisms in the motor incoordinating effect of ethanol and further supports our earlier suggestion for the role of adenosine in some of the central effects of ethanol.