Inhibition of biogenic amine uptake by hydrogen peroxide: a mechanism for toxic effects of 6-hydroxydopamine

Hydrogen peroxide, dialuric acid, or 6-hydroxydopamine inhibited the uptake of dopamine, norepinephrine, and serotonin into rat brain synaptosomal preparations. The addition of catalase protected all systems, but catalase was only partially protective for 6-hydroxydopamine acting upon catecholamine uptake. The data show that 6-hydroxydopamine generates hydrogen peroxide and that hydrogen peroxide can damage the biogenic amine uptake systems. Part of the damage caused by the 6-hydroxydopamine that accumulates in the catecholamine nerve terminals in vivo may be attributed to the hydrogen peroxide.     

Possible etiology of schizophrenia: progressive damage to the noradrenergic reward system by 6-hydroxydopamine

Single or repeated intraventricular injections of 6-hydroxydopamine caused marked and long-lasting deficits in brain self-stimulation and other rewarded behaviors in the rat. The behavioral deficits, as well as the depletion of brain norepinephrine induced by 6-hydroxydopamine, were prevented by prior treatment with chlorpromazine. Episodic or continuous formation of endogenous 6-hydroxydopamine in man as a result of a genetically determined enzymatic error could selectively damage the binding capacity and, eventually, the structural integrity of the noradrenergic reward mechanism. Such damage might cause the fundamental symptoms and long-term downhill course of schizophrenia.     

Uncus and amiygdala lesions: effects on social behavior in the free-ranging rhesus monkey

The eflect of uncinectomny on the social behavior of free-ranging rhesus monkeys was observed on Cayo Santiago Island. Operated subjects showed social indifjerence, failed to display appropriate aggressive and submissive gestures. were expelled from their social group, and evenitlually died. Two juvenile subjects with the lesion restricted to amygdala survived and have rejoinied their social group. Size of lesion and age at operation were major factors in determniting the degree of behavioral change.     

6-Hydroxydopamine: evidence for superoxide radical as an oxidative intermediate

Superoxide dismutase inhibited the autoxidation of 6-hydroxydopamine as measured by the rate of formation of a quinone and the rate of oxygen consumption. These observations demonstrate the formation of the superoxide radical during the autoxidation process. This finding may be relevant to the mechanism of adrenergic nerve terminal degeneration caused by 6-hydroxydopamine.     

Rank of mothers and sons in bands of rhesus monkeys

In bands of free-ranging macaques, adolescent males typically leave their mothers in the central part of the band and assume low social rank at the periphery. But the adolescent sons of high-ranking mothers may remain central and rise to high rank without becoming peripheral.     

Deficits in feeding behavior after intraventricular injection of 6-hydroxydopamine in rats

Intraventricular injections of 6-hydroxydopamine produced 95 percent depletion of telencephalic norepinephrine and 62 percent depletion of striatal dopamine in rats. Treated rats maintained body weight at subnormal levels and failed to increase food intake in response to a short-term decrease in glucose utilization. After treatment with the monoamine oxidase inhibitor pargyline, 6-hydroxydopamine produced no further norepinephrine depletion but increased the dopamnine depletion to 95 percent and produced complete aphagia. These effects are comparable to events that follow bilateral electrolytic lesions of the lateral hypothalanmus.     

Brain noradrenergic systems as a prerequisite for developing tolerance to barbiturates

Mice treated with 6-hydroxydopamine before they were chronically fed phenobarbital did not develop functional barbiturate tolerance, measured by duration of the loss of righting reflex and hypothermia. Injection of 6-hydroxydopamine caused significant depletion of brain norepinephrine, while brain dopamine levels were not significantly depleted. Intact brain noradrenergic systems seem to be necessary for developing tolerance to the hypnotic and hypothermic effects of the barbiturates.     

Social communication in canids: evidence for the evolution of a stereotyped Mammalian display

The variability in the duration and form of the canid play bow was studied in infant coyotes, wolves, wolf-dog hybrids, beagles, and adult free-ranging dogs. Both duration and form showed marked stereotypy. It appears that the role of this context-specific social signal in the communication of play intention has been fostered by selection for "morphological" stereotypy.     

Overeating and obesity from damage to a noradrenergic system in the brain

A discrete, ascending fiber system that supplies the hypothalamus with most of its noradrenergic terminals was destroyed at midbrain level, both electrolytically and with local injections of 6-hydroxydopamine, a destructive agent specific for catecholaminergic neurons. The result was hyperphagia leading to obesity. Fluorescence histochemical analysis showed that loss of noradrenergic terminals in ventral bundle termination areas such as the hypothalamus was necessary for hyperphagia. Damage to dorsal bundle or dopaminergic projections was not. Prior treatment with desmethylimipramine to selectively block uptake of 6-hydroxydopamine into noradrenergic neurons prevented both hyperphagia and loss of norepinephrine fluorescence. The lesions that produced hyperphagia also reduced the potency of d-amphetamine as an appetite suppressant. It is concluded that this noradrenergic bundle normally mediates suppression of feeding, thereby influences body weight, and serves as a substrate for d-amphetamine-induced loss of appetite.     

Adrenal tyrosine hydroxylase: compensatory increase in activity after chemical sympathectomy

Destruction of peripheral sympathetic nerve endings with 6-hydroxydopamine causes a disappearance of cardiac tyrosine hydroxylase, accompanied by a twofold increase in adrenal tyrosine hydroxylase and a small increase in phenyl-ethanolanine-N-methyl transferase. No change in adrenal catecholamine content occurs under these conditions.     

广西猪群肠道寄生虫感染情况调查

【目的】摸清广西区规模化猪场和散养户猪群肠道寄生虫的流行情况,旨在为养殖户提供预防及控制猪寄生虫病的科学依据。【方法】通过直接涂片法、沉淀法、尼龙筛淘洗法、卢氏碘液染色法、蔗糖溶液漂浮法等对广西12个市的规模化猪场和散养户猪群共3021份样品进行肠道寄生虫感染情况调查。【结果】广西猪群感染的肠道寄生虫主要有猪球虫、小袋纤毛虫、线虫和隐孢子虫,小袋纤毛虫和猪球虫的感染虽然比较普遍,但感染强度均较低,属于正常带虫现象。广西规模化猪场中线虫感染率最高的是类圆线虫（2．26％）,其次是鞭虫（0．98％）和蛔虫（0．81％）,食道口线虫最低（0．58％）;在广西散养户猪群中,线虫感染率最高的是蛔虫和鞭虫,均为8．19％,最低是食道口线虫（4．56％）。0-6月龄猪群中各种线虫的感染率随着日龄的增长而增长,但6月龄以后,线虫感染率在规模化场猪趋于平缓,散养户猪群则明显下降。【结论】广西猪群仍然存在寄生虫感染的危害,其中线虫的优势虫种是猪蛔虫和鞭虫,即广西当前甚至未来几年内,猪群需要重点防范的体内寄生线虫仍是蛔虫和鞭虫。     

广西猪群肠道寄生虫感染情况调查

【目的】摸清广西区规模化猪场和散养户猪群肠道寄生虫的流行情况,旨在为养殖户提供预防及控制猪寄生虫病的科学依据。【方法】通过直接涂片法、沉淀法、尼龙筛淘洗法、卢氏碘液染色法、蔗糖溶液漂浮法等对广西12个市的规模化猪场和散养户猪群共3021份样品进行肠道寄生虫感染情况调查。【结果】广西猪群感染的肠道寄生虫主要有猪球虫、小袋纤毛虫、线虫和隐孢子虫,小袋纤毛虫和猪球虫的感染虽然比较普遍,但感染强度均较低,属于正常带虫现象。广西规模化猪场中线虫感染率最高的是类圆线虫（2.26%）,其次是鞭虫（0.98%）和蛔虫（0.81%）,食道口线虫最低（0.58%）;在广西散养户猪群中,线虫感染率最高的是蛔虫和鞭虫,均为8.19%,最低是食道口线虫（4.56%）。0~6月龄猪群中各种线虫的感染率随着日龄的增长而增长,但6月龄以后,线虫感染率在规模化场猪趋于平缓,散养户猪群则明显下降。【结论】广西猪群仍然存在寄生虫感染的危害,其中线虫的优势虫种是猪蛔虫和鞭虫,即广西当前甚至未来几年内,猪群需要重点防范的体内寄生线虫仍是蛔虫和鞭虫。     

Tetrahydrobiopterin in striatum: localization in dopamine nerve terminals and role in catecholamine synthesis

The hydroxylase cofactor, tetrahydrobiopterin, and its biosynthetic system are localized in dopaminergic nerve terminals in the striatum. This conclusion is based on the nearly equivalent loss of tyrosine hydroxylase and tetrahydrobiopterin and its initial biosynthetic enzyme, guanosine triphosphate cyclohydrolase, after injection of 6-hydroxydopamine into the substantia nigra. The role of the hydroxylase cofactor in the regulation of dopamine synthesis is reassessed.     

Reversal by L-dopa of impaired learning due to destruction of the dopaminergic nigro-neostriatal projection

Rats receiving bilateral stereotaxic injections of 6-hydroxydopamine into the zona compacta of the substantia nigra failed to learn a one-way active avoidance response. Small doses of L-dopa (1.5 milligrams per kilogram of body weight) in combination with a peripheral decarboxylase inhibitor reversed this impairment. Animals with lesions which acquired the avoidance response during L-dopa administration retained this response when drug treatment was discontinued. These experiments suggest that the dopaminergic nigro-neostriatal projection serves a critical function in the acquisition of learned instrumental responses.     

Serum dopamine- -hydroxylase: decrease after chemical sympathectomy

Dopamine-beta- hydroxylase is an enzyme that is localized to catecholamine-containing vesicles in sympathetic nerves and the adrenal medulla, and is also found in the serum. Treatment of rats with 6-hydroxydopamine, a drug which destroys sympathetic nerve terminals, leads to a decrease in serum dopamine-beta-hydroxylase activity. The decrease is not due to an effect on the adrenal medulla or to an increase in circulating inhibitor or inhibitors of enzyme. These data represent evidence that at least a portion of the circulating dopamine-beta-hydroxylase activity arises from sympathetic nerve terminals.     

Lesions of central norepinephrine terminals with 6-OH-dopamine: biochemistry and fine structure

Intracisternal injections of 6-hydroxydopamine produce rapid and long-lasting depletion of brain catecholamines without effects on serotonin concentrations. Depletion of norepinephrine is greatest in areas containing only nerve terminals and axons and least in areas containing monoamine cell bodies. The norepinephrine loss is accompanied by electron microscopic evidence of nerve terminal degeneration and decreased turnover. Dopamine loss is less marked and is not accompanied by degeneration or alteration of turnover rate.     

Presynaptic location and axonal transport of beta 1-adrenoreceptors in the rat brain

Interruption of the ascending noradrenergic neurons of the locus coeruleus in the rat forebrain with 6-hydroxydopamine produced a progressive accumulation, proximal to the lesion, of tritiated dihydroalprenolol binding activity over 2 days. This accumulation could be blocked by interrupting the neurons closer to their cell bodies. Competitive binding studies with the beta 2 agonist Zinterol suggested that the accumulated beta-receptors were primarily of the beta 1 subtype. These results suggest that, in the rat brain, some beta 1-adrenoreceptors are located in presynaptic, noradrenergic locus coeruleus neurons and are transported in their axons.     

Adrenergic innervation of the parasympathetic ciliary ganglion in the chick

The chick ciliary ganglion receives a nonvascular symathetic innervation in addition to the well-known cholinergic one; fluorescent, varicose adrenergic fibers form pericelluar baskets. Adrenergic fibes were identified electron microscopically in ganglia fixed with potassium permanganate. The fibers degenerate after injection of 6-hydroxydopamine. No true synaptic relationships involving adrenergic varicosities and ganglion cells or cholinergic terminals were demonstrable. The distribution of the adrenergic fibers suggests a kind of "distance à synapse" with the choroidal cells or with the preganglionic fibers (or both). The adrenergic innervation might provide a modulation of the cholinergic transmission.     

Organic practices and gender are effective strategies to provide healthy pork loin

This study evaluated the influence of husbandry(organic feed and management but not free-ranging vs. conventional) and sex(barrows vs. gilts) on pork meat quality. A total of 60 Longissimus thoracis pork muscle samples from different 3-way crossbred genotypes were chosen from 3 conventional and 2 organic pig farms. Technological meat quality was measured at 24 h post-mortem and muscle fatty acid content and composition was analysed by gas chromatography. The loin from organic pigs at 24 h of retail display had lower pH, but it had no detrimental effects on drip loss. All the International Commission on Illumination colour attributes except meat lightness differed between husbandry systems. Moisture and crude protein content were lower whereas intramuscular fat content was greater in organic than in conventional pork. Total saturated fatty acid(SFA), monounsaturated fatty acid(MUFA), polyunsaturated fatty acid(PUFA) and PUFA n-6 contents did not differ between husbandry systems, but total PUFA n-3(mainly C18:3 n-3) were greater in organic than in conventional pork. Sex did not affect ultimate p H or meat colour attributes but barrows showed lower moisture and greater intramuscular fat than gilts. Total SFA and MUFA content were similar but all the PUFA(both n-6 and n-3) were lower in barrows than in gilts. These results suggest that some bioactive compounds from dietary origin, i.e., linolenic acid(C18:3 n-3) content from dietary vegetable oils(soybean or olive olein), might be used to highlight the nutritive value of(not free-ranging) organic pork meat. In addition, gilts were leaner than barrows and showed a more favourable PUFA/SFA ratio.     

L-Dopa-induced release of cerebral monoamines

L-Dopa markedly increased the efflux of tritiated dopamine and tritiated serotonin from rat brain slices. This action appeared contingent on the decarboxylation of L-dopa to dopamine, since it could be blocked by an inhibitor of L-amino acid decarboxylase. Selective destruction of catecholamine-containing nerve terminals by 6-hydroxydopamine significantly decreased the uptake and release of tritiated dopamine but not that of tritiated serotonin. These observations support the hypothesis that a portion of exogenously administered L-dopa may enter central serotonin terminals and undergo decarboxylation to the amine with resultant displacement of the endogenous indoleamine from vesicular stores.