Can the essential oil of rosemary (Rosmarinus officinalis Linn.) protect rats infected with itraconazole-resistant Sporothrix brasiliensis from fungal spread?

INTRODUCTION: Itraconazole is the first-choice option to treat human and animal sporotrichosis. However, the emergence of itraconazole-resistant strains has encouraged research on new active antifungals. Among them, the essential oil of rosemary (Rosmarinus officinalis Linn., Lamiaceae) has shown antifungal activity in vitro. OBJECTIVE: Assessing, for the first time, the effectiveness of rosemary essential oil in vivo in experimental cutaneous sporotrichosis, as well as its chemical composition and action mode. METHODS: Itraconazole-resistant Sporothrix brasiliensis was inoculated in the left foot pad of 30 Wistar rats, which were randomized (n=10) for treatment with saline solution (control, CONT), itraconazole (ITRA, 10 mg/kg) and rosemary oil (ROSM, 250 mg/kg) for 30 days at an oral dose of 1 mL, daily. Clinical evolution, histopathology and fungal burden were investigated. GC-MS was used for chemical analysis; sorbitol protection and ergosterol effect were used to evaluate the action mechanism of rosemary oil. RESULTS: ROSM was the only group evolving to skin lesion remission, lack of edema and exudate, and mild-to-absent yeast cells. Rosemary oil delayed fungal spreading and protected systemic organs, mainly liver and spleen. The ROSM group presented lower fungal load than that observed for the CONT and ITRA groups (p<0.05). Antifungal action took place at complexation level after ergosterol application. Most compounds were 1,8-cineole/eucalyptol (47.91%), camphor (17.92%), and α-pinene (11.52%). CONCLUSIONS: These findings have evidenced that rosemary oil is a promising antifungal to treat sporotrichosis, since it protects systemic organs from fungal spread.

Chemical and cytotoxic analyses of three varieties of Brazilian propolis (green propolis, jataí propolis and brown propolis) and its anti-Sporothrix brasiliensis in vitro activity / [Análises químicas e citotóxicas de três variedades de própolis brasileiras (própolis verde, própolis jataí e própolis marrom) e sua atividade in vitro anti-Sporothrix brasiliensis]

In this study, we described the antifungal activity of three Brazilian propolis extracts: brown, green and from jataí bees against Sporothrix brasiliensis. The extracts were obtained from ethanolic extraction and their chemical composition was determined by high-performance liquid chromatography coupled to mass spectrometry. The cellular toxicity was measured in MDBK (Madin-Darby Bovine Kidney) cells and quantified by the MTT assay (3- (4,5 dimethylthiazol-2yl -2,5-diphenyl-2H bromine tetrazolato). For antifungal activity, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined by broth microdilution. The results showed that cell toxicity was not observed at lower concentrations (0.097 to 0.39μg/ml) for all extracts in comparison to cell control. Among the chemical compounds identified, caffeic acid, p-coumaric acid, chlorogenic acid, ferulic acid and rutin were quantified. In antifungal activity, green and jataí did not exhibit activity against the isolates (MIC and MFC greater than 0.78mg/ml). However, all isolates of S. brasiliensis were sensitive to brown propolis (MIC of 0.09 to 0.78mg/ml), including the standard strain (P<0.001). Among the Brazilian propolis studied, the brown propolis showed activity against the S. brasiliensis isolates and more studies should be undertaken in order to evaluate its promising use in the treatment of sporotrichosis.(AU)

Neste estudo, descreveu-se a atividade antifúngica de três extratos de própolis brasileiras: marrom, verde e de abelhas jataí (Tetragonisca angustula), contra Sporothrix brasiliensis. Os extratos foram obtidos de extração etanólica, e a sua composição química foi determinada por cromatografia líquida de alta eficiência, acoplada à espectrometria de massa. A toxicidade celular foi medida em células MDBK (Madin-Darby Bovine Kidney), avaliada por observação microscópica e quantificada pelo ensaio MTT (3- (4,5-dimetiltiazol-2-ilo -2,5-difenil-2H bromo tetrazolato). Para a atividade antifúngica, determinou-se a concentração inibitória mínima (CIM) e a concentração fungicida mínima (CFM) por meio de microdiluição em caldo. Os resultados mostraram que a toxicidade celular não foi observada em concentrações menores (0,097 a 0,39μg/ml). Entre os compostos químicos identificados, foram quantificados o ácido cafeico, ácido p-cumárico, ácido clorogênico, ácido ferúlico e a rutina. Na atividade antifúngica, as própolis verde e jataí não apresentaram atividade contra os isolados (CIM e CFM maior que 0,78mg/ml), porém todos os isolados de S. brasiliensis foram sensíveis à própolis marrom (CIM de 0,09 a 0,78mg/ml), incluindo a cepa padrão (P<0,001). Entre as própolis brasileiras estudadas, a marrom mostrou atividade contra S. brasiliensis, e mais estudos devem ser realizados para avaliar seu uso promissor no tratamento da esporotricose.(AU)

Effects of essential oils of Rosmarinus officinalis Linn. and Origanum vulgare Linn. from different origins on Sporothrix brasiliensis and Sporothrix schenckii complex / Efeitos dos óleos essenciais de Rosmarinus officinalis Linn. e Origanum vulgare Linn. de diferentes origens em Sporothrix brasiliensis e complexo Sporothrix schenckii

Rosmarinus officinalis L. (rosemary) and Origanum vulgare L. (oregano) are known to have antimicrobial properties, but studies on sporotrichosis are scarce. This study aimed to evaluate the anti-Sporothrix spp. activity of essential oils from commercial products and oils extracted from aerial parts of these plants and analyze their chemical constituents. S. schenckii complex and S. brasiliensis (n: 25) isolated from humans, cats, dogs, and environmental soil were tested through M27-A3 guidelines of CLSI with modification for phytotherapics. The essential oils of R. officinalis L. were similar for MIC50 and MFC50 ≤2.25mg/mL for extracted oil; and 4.5mg/mL and 9mg/mL, respectively, for commercial oil. Both products showed MIC90 of 18mg/mL and MFC90 of 36mg/mL. In O. vulgare L., the extracted oil had better activity with MIC50 and MFC50 ≤2.25mg/mL, and MIC90 and MFC90 of 4.5mg/mL, whereas the commercial oil showed MIC50 and MFC50 of 9mg/mL and MIC90 18mg/mL, respectively, and MFC90 of 36mg/mL. Through gas chromatography (CG/FID), thymol and α-terpinene were majority for extracted oil of O. vulgare L., and carvacrol and γ-terpinene made up the majority of the commercial oil. Both essential oils of R. officinalis L. showed 1,8-cineole and α-pinene as major. The fungal isolates were susceptible to all tested essential oils, including in itraconazole-resistant S. brasiliensis isolates. The extracted and commercial oils of the plants presented in vitro anti-Sporothrix spp. activity, and they are promising for treatment of sporotrichosis, including in cases refractory to itraconazole. More studies should be performed about toxicity and in vivo efficacy for its safe use.(AU)

Rosmarinus officinalis L. (alecrim) e Origanum vulgare L. (orégano) são conhecidos pelas propriedades antimicrobianas, entretanto seus estudos na esporotricose são escassos. Este trabalho objetivou avaliar a atividade anti-Sporothrix spp. de óleos extraídos e comerciais dessas plantas e analisar seus constituintes químicos. Isolados do complexo S. schenckii e S. brasiliensis (n: 25) de humanos, gatos, cães e solo, foram testados pela diretriz M27-A3 do CLSI com modificações para fitoterápicos. Os óleos de R. officinalis L. foram similares com CIM50 e CFM50 ≤2.25mg/mL para extraído; e 4.5mg/mL e 9mg/mL, respectivamente, para comercial. Ambos os produtos demonstraram CIM90 de 18mg/mL e CFM90 de 36mg/mL. Em O. vulgare L., o óleo extraído apresentou melhor atividade com CIM50 e CFM50≤2.25mg/mL e CIM90 e CFM90 de 4.5mg/mL, ao passo que o óleo comercial mostrou CIM50 e CFM50 de 9mg/mL; e CIM90 de 18mg/mL e CFM90 de 36mg/mL. Por meio da cromatografia gasosa (CG/FID), timol e α-terpineno foram majoritários para o óleo extraído de O. vulgare L., e carvacrol e γ-terpineno para o comercial. Ambos os óleos de R. officinalis L. apresentaram 1,8-cineol e α-pineno como prevalentes. Os isolados foram sensíveis a todos os óleos essenciais testados, inclusive S. brasiliensis, resistentes ao itraconazol. Os óleos extraídos e comerciais de R. officinalis L. e O. vulgare L. apresentaram atividade anti-Sporothrix spp. in vitro e são promissores para o tratamento da esporotricose, inclusive em casos refratários ao itraconazol. Mais estudos devem ser realizados sobre toxicidade e eficácia in vivo para seu uso seguro.(AU)

Temporal profile of neurochemical recovery following injury by transient cerebral ischemia.

The effects of transient cerebral ischemia by the four-vessel occlusion model on balance beam performance and regional activity of glutamic acid decarboxylase (GAD) and choline acetyltransferase (ChAT) and muscarinic binding (MusBnd) were evaluated over a six-month postischemia period in 6- and 24-month-old rats. Cerebral ischemia resulted in an early reduction in balance beam performance in young and old rats that partially recovered. GAD in young and old animals and ChAT in old animals and MusBnd in young and old animals were also significantly altered by ischemia. There was partial recovery of each neurochemical marker noted. In some cases the recovery was partially accounted for by the absence of any age-associated changes in the ischemic group. The results of the present study suggest an age-dependent vulnerability to ischemic injury occurs and that aged brain's gamma-aminobutyric and cholinergic systems are capable of measurable recovery.

Effects of deferoxamine and a diet deficient in vitamin E on isoelectric electroencephalographic responses associated with ischemia by the four vessel occlusion method.

This study reports the effects of subchronic administration of the iron chelator deferoxamine (4.2 mg/day by osmotic minipump for 6 days) and a diet deficient in Vitamin E (15% RDA for 60 days) on the isoelectric electroencephalographic responses associated with 15 minutes of global transient cerebral ischemia in rats. Brain levels of thiobarbiturate-reacting substance (TBARS), a measure of lipid peroxidation, were lower in deferoxamine-treated animals and higher in Vitamin E deficit animals suggesting the treatments altered free radical activity at the time of ischemia. During ischemia, all test animals were observed to lose the righting reflex and enter a quiescent state. Fifty percent of the animals in two control groups (N = 15 per group) demonstrated an isoelectric electroencephalographic pattern (defined as 10% or less of pre-ischemia total EEG power) with a mean onset of 5.44 minutes. One third of the animals treated with deferoxamine (N = 15) experienced an isoelectric encephalogram with a mean onset of 8.6 minutes and 73% of the Vitamin E-deficient group (N = 15) experienced an isoelectric EEG with a mean onset of 3.43 minutes. Following reperfusion, EEG patterns returned to power levels within 20% of pre-ischemia levels in all animals. Control animals obtained this EEG power level within 1.34 minutes, deferoxamine-treated animals within 1.25 minutes and animals provided a diet deficient in Vitamin E within 5.03 minutes. Compared to mean total EEG power prior to the onset of ischemia, mean total EEG power five days after reperfusion was reduced 14% in the control groups and 59% in the Vitamin E-deficient group and increased 123% in the deferoxamine group. Results are discussed in relation to the possible involvement of free radicals in the ischemic and postischemic process.

Nicotinic binding sites in cerebral cortex and hippocampus in Alzheimer's dementia.

Postmortem cerebral neocortical and hippocampal samples were taken from patients who died with dementia of the Alzheimer type (DAT) and individuals without diagnoses of neurological or psychiatric disease (control). Nicotinic binding was assayed with 20 nM [3H]acetylcholine [( 3H]ACh) in the presence of atropine, or with 4 nM (-)-[3H]nicotine ((-)-[3H]Nic). Binding of both ligands was lower in the following regions from DAT vs. control brains (P less than or equal to 0.05): superior, middle and inferior temporal gyri, orbital frontal gyrus, middle frontal gyrus, pre- and postcentral gyri, inferior parietal lobule, and hippocampal endplate. Values of the correlation coefficient (r's) for binding of the nicotinic cholinergic ligands in these regions ranged from 0.70 to 0.93 (P's less than 0.05), suggesting that [3H]ACh and (-)-[3H]Nic labeled the same sites in human brain. There was no difference in nicotinic binding in the presubiculum, comparing DAT and control samples (P greater than 0.05). Here too, correlations between binding of the two ligands were statistically significant in control and DAT groups (r's = 0.92, P's less than 0.05). Nicotinic binding measured with [3H]ACh, but not (-)-[3H]Nic, was significantly lower in the H2 (field of Rose) and H1-subiculum areas of DAT samples compared to control. Correlations between binding of the two ligands in these regions ranged from 0.21 to 0.34 for the two groups (P's greater than 0.05). The findings support a loss of neocortical and hippocampal nicotinic cholinergic binding sites in DAT.(ABSTRACT TRUNCATED AT 250 WORDS)

Choline acetyltransferase activity and muscarinic binding in brain regions of aging fischer-344 rats.

Muscarinic receptor binding and choline acetyltransferase (EC 2.3.1.6.) activity were assayed in three brain regions of 4-, 12- and 24-month-old Fischer-344 rats. Statistically significant age differences in cholinergic parameters were observed in each region. The affinity for [(3)H]quinuclidinyl benzilate increased in the cortex (24 vs 12 and 4 months), but B(max) decreased in the cortex (24 vs 12 vs 4 months), striatum (24 vs 12 vs 4 months) and hippocampus (24 vs 12 and 24 vs 4). Assays of carbamylcholine inhibition of [(3)H]quinuclidinyl benzilate binding in the hippocampus showed that high affinity agonist binding increased with age (24 vs 12 and 4 months), and the percentage of muscarinic binding to high affinity agonist sites decreased (24 vs 12 vs 4 months). In addition, the affinity of the agonist oxotremorine for muscarinic binding sites also increased in the hippocampus (12 and 24 vs 4 months). Although the K(m) of choline acetyltransferase for choline chloride did not change in any region tested, the K(m) for acetyl coenzyme A decreased in the hippocampus (24 vs 12 months), but increased (4 vs 12 months) and then decreased (12 vs 24 months) in the striatum. Statistically significant age-related declines in V(max) for choline acetyltransferase were noted in the striatum (24 < 12 < 4 months), but no age differences in this parameter were observed in the cortex or the hippocampus. Statistically significant positive correlations between V(max) for choline acetyltransferase and B(max) for [(3)H]quinuclidinyl benzilate binding were observed in each of the brain regions of 4-, 12- and 24-month-old rats. The findings have implications for use of the Fischer-344 male rat as an animal model of aging and age-related disorders of the human brain, including dementia of the Alzheimer type.

Muscarinic binding and choline acetyltransferase in postmortem brains of demented patients.

Postmortem human brain samples were taken from non-neurological controls as well as demented subjects who died with Alzheimer's disease (AD), multi-infarct dementia (MID), or a combination of AD and MID dementia (MIXED). Choline acetyltransferase (ChAT) activity was measured radiometrically using [1-14C]acetyl-coenzyme A as the substrate, muscarinic binding was assayed with [3H]quinuclidinyl benzilate, and the proportion of binding associated with high affinity agonist sites was measured by carbamylcholine displacement of the radioligand. Relative to control, ChAT activity was significantly reduced (p less than or equal to 0.01) in samples taken from the temporal, frontal, and hippocampal areas of demented patients. A small elevation in Bmax was noted in the hippocampal endplate (p less than or equal to 0.01) (AD vs. control) and the H1-subiculum region (p less than or equal to 0.05) (AD vs. all other groups). In addition, the percentage of binding associated with high affinity agonist sites was greater in the frontal cortex of AD and MID samples (p less than or equal to 0.05). The results suggest a regionally specific upregulation of cerebral muscarinic receptors in dementia, especially in AD.

Convulsive thresholds and severity and the anticonvulsant effect of phenobarbital and phenytoin in adult rats administered 6-hydroxydopamine or 5,7-dihydroxytryptamine during postnatal development.

Rats were administered intracisternal 6-hydroxydopamine (6-OHDA) or 5,7-dihydroxytryptamine (5,7-DHT) within the first three postnatal days, at several ages centered on the third postnatal week or on postnatal day 180. When the rats were 210-days-old, maximal electroshock convulsive thresholds and responses and the anticonvulsant effect of phenobarbital and phenytoin were determined. All 5,7-DHT treatments resulted in an approximate 21% decrease in the tonic convulsive threshold and increased the incidence of tonic hindlimb extension (HLE). Only the 5,7-DHT treatment at 180 days was associated with a more severe HLE response (shortened onset and prolonged duration). All neonatal 6-OHDA treatments were associated with no change in the tonic threshold, but increased the incidence and severity of HLE. The latter effect depended on the postnatal age of 6-OHDA-treatment: treatment at postnatal days 14 and 15 resulted in the greatest increase in severity (52% decrease in onset and 48% increase in duration). The 6-OHDA treatment to 180-day-old rats increased the incidence and duration of HLE but had no influence on the tonic threshold or onset of extension. The effectiveness of both phenobarbital and phenytoin to block HLE was variably decreased by all neurotoxin treatments. The results suggest that interference with the postnatal maturation of monoaminergic influences on seizure processes can have a long-lasting influence on the ability of the brain to limit the generation and spread of seizure activity and on the effectiveness of anticonvulsant drugs.

Discrimination learning requiring different memory components in rats: age and neurochemical comparisons.

The performances of young (8-9 months) and aged (22-24 months) male ACI rats were compared in a T-maze requiring two discriminations, each of which placed different demands on memory processing. A spatial discrimination in the stem of the T-maze required long-term reference memory; a discrete-trial, alternation discrimination in the arms of the T-maze required working memory. Following acquisition training in one maze, rats were also trained in a second maze at a different location in the room. The correct response in the stem of this maze was opposite to that in the first maze. In two experiments with slightly different pretraining procedures, similar results demonstrated that aged rats made more errors in all phases of maze training than did their young counterparts. The results suggest that all components of memory processing were affected equivalently because the age-related impairment was not selectively greater in any component of the task. In a third experiment, aged rats were unimpaired in the ability to perform in a T-maze task involving a brightness discrimination with intramaze cues. This result suggests that the age-related impairment in the two-component T-maze task was restricted to the cognitive demands of the task. Neurochemical analyses were performed to determine whether regional neurotransmitter synthetic enzyme activities could be used to identify neurochemical systems associated with performance in these tasks and with any age-related impairments observed. Choline acetyltransferase and glutamic acid decarboxylase were assayed as markers for cholinergic and GABAergic systems, respectively, in the hippocampi and the following cortical regions: frontal, sensorimotor, auditory, cingulate, occipital, and pyriform-perirhinal. A slight (8%) but significant age-related decline was observed in the activity of glutamic acid decarboxylase but not of choline acetyltransferase. Although the correlation between maze performance and regional enzyme activities generally supported several previous observations, the only significant correlation to emerge was between working memory performance and glutamic acid decarboxylase activity in the cingulate cortex.

Radial maze performance in young and aged mice: neurochemical correlates.

Young (8 month) and aged (27-28 month) male C57BL/6J mice were trained in a spatial discrimination task requiring working memory. The mice were tested during three trials daily in an eight-arm radial maze for 36 test days. Correct choices were reinforced with isotonic saline. In contrast to past reports, young mice learned the task. Old mice also learned the task, and no significant age-related differences in performance were observed. Following maze training, the mice were killed, the brains removed, and the specific activities of choline acetyltransferase (E.C.2.3.1.6., ChAT) and L-glutamic acid decarboxylase (E.C.4.1.1.15., GAD) were assayed in the hippocampus, and in frontal, sensorimotor, and cingulate areas of the cerebral cortex. The activities of these neurotransmitter synthetic enzymes did not differ significantly between young and old mice. Correct responding in the radial maze was positively correlated to ChAT activity in the cingulate cortex and negatively correlated to ChAT activity in the sensorimotor cortex. There was a similar pattern of correlation between performance and regional GAD activity, although none of the correlations involving GAD reached statistical significance.

Effects of intermittent feeding on neurochemical markers in aging rat brain.

Male Wistar rats were fed a diet of 24% protein either ad lib (AL) or every other day (EOD) beginning shortly after weaning. Rats were killed at 6 or 24-months of age. The corpus striatum, cerebral cortex, hippocampus, and cerebellum were assayed for muscarinic cholinergic receptor binding and the activities of choline acetyltransferase (ChAT), L-glutamic acid decarboxylase (GAD) and tyrosine hydroxylase (TH). Sensecent rats maintained on EOD feeding schedules from weaning showed a markedly higher density of striatal muscarinic binding sites and higher activities of cerebellar, hippocampal, and striatal ChAT, as compared with values in AL-fed rats. Regional GAD and TH activities were relatively unaffected by EOD feeding; however, at 6 months, EOD-fed rats had higher cortical GAD and lower cortical TH activities than corresponding AL-fed rats. EOD feeding for only 2 weeks produced no significant effects on neurochemical parameters examined in 24-month-old rats. We conclude that EOD feeding from weaning can alter neurochemical markers of senescence in rat brain; that cholinergic systems are affected in particular; and that the observed alterations produced by EOD feeding represent chronic rather than acute effects.

Indices of neurotransmitter synthesis and release in aging sympathetic nervous system.

Activities of tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and choline acetyltransferase (ChAT) were assayed in sympathetic ganglia and adrenal glands of young and aged Fischer-344 rats. The recovery of reserpine-depleted catecholamine stores and catecholamine loss following inhibition of synthesis and intraneuronal degradation also were assessed in sympathetic ganglia of young and aged rats. No age differences were observed in DBH activity of any tissues examined or in the activities of any enzymes in the coeliac-mesenteric ganglion complex. However, TH and ChAT activities were significantly higher in the superior cervical ganglia and adrenal glands of aged rats. In the hypogastric ganglion, only TH activity was higher in the old rats. Recoveries of reserpine-depleted catecholamine stores in the superior cervical and hypogastric ganglia of aged rats were slower than in young rats. Catecholamine loss following inhibition of synthesis and intraneuronal degradation was faster in the superior cervical ganglia but not in the hypogastric ganglia of old rats as compared with young rats. These findings suggest that neurotransmitter synthesis and release are enhanced with age in the superior cervical ganglion. The lack of age-related changes in the hypogastric ganglion might reflect the different cellular composition as well as the physiological role of this ganglion.

Autoradiographic localization of [3H]nicotine binding sites in the rat brain.

In vitro autoradiography was used to visualize [3H]nicotine binding sites in the rat brain. Labeling was densest in the interpeduncular nucleus and medial habenula but was also detected in thalamic nuclei, areas related to sensory function, the cerebral cortex, and molecular layer of the dentate gyrus. Specific binding was sparse in the hypothalamus and caudate-putamen, and not detected in Ammon's horn of the hippocampus or in the periaqueductal grey matter. These findings may relate to the distribution of nicotine's cerebral loci of action.

Tonic convulsive thresholds and responses during the postnatal development of rats administered 6-hydroxydopamine or 5,7-dihydroxytryptamine within three days following birth.

The maturation of the electroshock tonic convulsive pattern and threshold was investigated in rats between the ages of 4 and 30 days following intracisternal injections of 6-hydroxydopamine (6-OHDA) on postnatal days 1 and 2; or 5,7-dihydroxytryptamine (5,7-DHT) after desipramine on postnatal day 3. In 6-OHDA treated rats decreases in brain norepinephrine (mean values of 55% of control) and dopamine (mean values of 17% of control) were associated with a large reduction in the convulsive threshold and intensification of the pattern on postnatal day 4. Whereas the reduction in catecholamine concentrations and the intensification of the pattern were still evident on postnatal day 30, the last day of testing, the threshold effect was not evident by postnatal day 15. Although 5,7-DHT reduced brain serotonin concentrations (mean values of 59% of control) as early as postnatal day 4, the pattern was not intensified until postnatal day 8, and the threshold was not reduced until postnatal day 21. These effects were still evident on postnatal day 30. The results demonstrate a sequential maturation of monoaminergic regulation in seizure susceptibility and severity, with an apparent transition from catecholaminergic to serotonergic regulation of the tonic threshold during the third postnatal week.

Age and strain comparisons of neurotransmitter synthetic enzyme activities in the mouse.

Activities of the neurotransmitter synthetic enzymes, choline acetyltransferase (EC 2.3.1.6; ChAT), glutamic acid decarboxylase (EC 4.1.1.15; GAD), and tyrosine hydroxylase (EC 1.14.3.2; TH), were assayed in four brain regions of A/J and C57BL/6J mice at three ages (4, 18, and 24 months). The brain regions assayed were the fronto-parietal cortex, hippocampus, striatum, and cerebellum. Strain effects: In some brain regions, at several ages, ChAT activity did not differ among the two strains. However, ChAT was higher in the C57BL/6J strain in the cortex at 18 months, the hippocampus at 18 and 24 months, the striatum at 24 months, and the cerebellum at 4 months. The reverse was true in the cerebellum at 24 months, where ChAT was higher in A/J mice. GAD activity in C57BL/6J mice compared to that of A/J mice was higher in the striatum and cortex, and lower in the hippocampus and cerebellum. TH activities in all four regions were generally higher in C57BL/6J mice than in A/J mice. Age effects: Age differences in enzyme activities varied with the genetic strain. ChAT activity generally was higher in brain regions of older mice of both strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-dependent correlation of motor performance with neurotransmitter synthetic enzyme activities in mice.

The performance of male C57BL/6J mice (Mus musculus) was assessed in a battery of tests designed to detect age-related losses in motor abilities and also to examine individual differences within age groups. Studied were 4-, 18-, and 24-month-old mice. Within 5 days following the completion of the behavioral battery, the mice were killed, and brain tissue was taken for determinations of choline acetyltransferase (EC 2.3.1.6), L-glutamic acid decarboxylase (EC 4.1.1.15) and tyrosine hydroxylase (EC 1.14.16.2) activities in the frontoparietal + temporal + occipital cortex, hippocampus, striatum, and cerebellum. Two composite test scores were derived for each animal. The first composite score comprised measurements of locomotor activity, and the second reflected strength and coordination abilities. Test scores included in each composite correlated highly with that composite score, but not with the other composite. This observation suggests that there is a high degree of internal consistency for the composite scores and that the composite scores represent independent behavioral factors. Significant correlations between the composite scores and regional enzyme activities were detected; these correlations varied with age. In most cases, the sign (+, -) of the correlation was reversed at 24 months as compared with 4 months of age. These results suggest that the relations between performance and enzyme activities vary with age, and may reflect altered neurotransmitter function during senescence. This work serves as an example of how direct correlational analyses may help to elucidate behavioral-neurochemical interactions in aging.

Age-differences in choline acetyltransferase activities and muscarinic receptor binding in brain regions of C57BL/6J mice.

Muscarinic receptor binding and choline acetyltransferase, (ChAT, EC.2.3.1.6.) activity were assayed in four brain regions of C57BL/6J mice of four ages (4, 12, 18, and 24 months). In the cerebellum, there were no age differences in either of the cholinergic markers. However, significant age differences were noted in the Vmax for ChAT and in the Bmax for [3H]quinuclidinyl benzilate ( [3H]QNB) in the cortex, striatum and hippocampus. Increases were noted in Vmax of the synthetic enzyme in all three regions and for Bmax in the hippocampus. Bmax for [3H]QNB decreased in the cortex and striatum. The high- and lower-affinity muscarinic binding constants, the percentage of muscarinic binding to high affinity sites determined by carbamylcholine displacement of [3H]QNB, as well as the affinities of ChAT for acetyl coenzyme A and choline chloride showed no age differences in any brain region.

Age-dependent reduction in maximum electroshock convulsive threshold associated with decreased concentrations of brain monoamines.

This study investigated modification of the tonic convulsive threshold to maximum electroshock in 15- and 30 day old rats treated with drugs which reduce steady-state concentrations of monoamines. On postnatal day 15, reduction of central catecholamine concentrations by 6-hydroxydopamine or of central serotonin concentrations by 5,7-dihydroxytryptamine or p-chloroamphetamine did not alter the tonic convulsive threshold. However, simultaneous depletion of catecholamines and serotonin by tetrabenazine was associated with a significant decrease in the tonic threshold. This effect could be reversed partially by simultaneous administration of the catecholamine and serotonin precursors, L-dihydroxyphenylalanine and 5-hydroxytryptophan, respectively. On postnatal day 30, reduction of brain serotonin concentration, but not catecholamine concentrations, was associated with a significant decrease of the tonic convulsive threshold. In a previous study, in which 7-8 day old rats were used, a tetrabenazine-induced decrease in the tonic convulsive threshold prevented by L-dihydroxyphenylalanine but not 5-hydroxytryptophan. Furthermore, intracisternal 6-hydroxydopamine, but not 5,7-dihydroxyhyptamine, decreased the threshold on postnatal day 8. Therefore, the results of the present day study involving 15- and 30 day old rats, together with the earlier findings in 7-8 day old rats, [28] suggest an apparent developmental transition from catecholaminergic to serotonergic dominance in regulation of the tonic convulsive threshold during the first postnatal month.