Participation of peptides in processes involved in the development of alimentary motivation in the rabbit

On the base of behavioural and electrophysiological experiments it was suggested that in rabbits the realization of the dominant feeding motivation into the goal-directed behaviour implied at the molecular-genetical level the operative synthesis of gastro-intestinal neuropeptide gastrin or its derivatives. It was supposed that the suppression of genetic information realization in CNS under blocking of peptide synthesis led to impossibility of goal-directed alimentary behaviour organization. This mechanism was found to be specific for alimentary behaviour; any its connection with defensive motivation realization was not observed.     

Substance P and effects of ethanol on the central mechanisms of the escape reaction in rabbits

Substance P (SP) effects on the central mechanisms of escape reaction, elicited by threshold electrical stimulation of the ventromedial hypothalamus were investigated in rabbits pretreated with ethanol (0.5 g/kg). SP (30 micrograms/kg) was demonstrated to normalize in 71.4% of cases the excitability of the ventromedial hypothalamus which was decreased by ethanol and restored in 83.3% of cases the facilitatory effects of the midbrain reticular formation in escape reactions. However, SP was ineffective in the restoration of the inhibitory effects of the dorsal hippocamp on the excitability of the ventromedial hypothalamus that was obvious in intact animals. Partial normalizing effect of SP on escape reaction in rabbits after previous ethanol administration can be accounted for by the fact that both undecapeptide and ethanol are similar in their realization of central effects such as an interaction with the same brain neurotransmitters, interference with neuronal enzyme processes and reactions with opiate receptors.     

Features of differential inhibition in choice between alimentary and defensive response

Instrumental defensive (avoidance/escape) and alimentary responses (reinforced with palatable food) in dogs were conditioned by the same stimulus (6-Hz light flashes). Differential inhibition for these responses (0.6-Hz flashes) was formed in unalterable series. Later on, alternative experiments with choice between reinforcements were carried out. In both of experimental series, the degree of alimentary excitability (hunger, satiation) was changed. Numbers of responses to differential and positive conditioned stimuli and their latencies were calculated. Under condition of choice (electrodes on a leg and a pedal in front of a dog) the response depended on a dominant motivation. The dogs differed in the degree of motivation dominance. Differential inhibition was less perfect in unalterable experimental series with dominant motivation. Under conditions of choice between alimentary and defensive reinforcements, the response to the differential stimuli depended on the balance between these motivations: two days of hunger increased the number of alimentary responses, defensive responses prevailed after satiation.     

乙醇加安定对家兔全身麻醉的实验研究

目的观察应用32%乙醇 安定对家兔的麻醉效果。方法对60只家兔随机分3组,分别静脉注射25%氨基甲酸乙酯、32%乙醇、32%乙醇 安定,观察麻醉起效时间、维持时间、全麻过程中动脉血压、心率和呼吸的变化。结果乙醇加安定的麻醉效果满意,成功率高。结论乙醇价廉,毒副作用小,乙醇加安定麻醉简单易行,安全可靠,适用于家兔手术实验。     

Effect of chronic ethanol treatment and subsequent ischaemia on phospholipids and cholesterol in the rabbit spinal cord

Rabbits received ethanol p.o. (0.96 g. ml-1, 2.88 g.kg-1) for 30 days. Ischaemia was induced by abdominal aorta ligation for 40 min in animals with or without ethanol treatment. The content of total (TPL) and individual phospholipids, i.e. ethanolamine (PE), choline (PC), serine (PS), phospholipids and sphingomyelin (SM), as well as unesterified cholesterol (UC) was determined in the gracilis fascicle (Fg), and the dorsal (Dp) and ventral (Vp) part of the lumbar and cervical spinal cord. Chronic ethanol treatment resulted in a statistically significant decrease in the PE content in Dp of cervical spinal cord. Cholesterol content was increased in all parts of the spinal cord studied (increased UC/TPL molar ratio). Ischaemia of the spinal cord induced a significant decrease in PI. In ethanolic animals ischaemia decreased the PS content in Dp and Vp of ischaemized lumbar spinal cord. The combined effect of ischaemia and chronic ethanol did not result in a cumulative pattern of changes suggesting a partially opposite influence of both stimuli on lipid metabolism as well as its altered regulation after chronic ethanol treatment in the spinal cord.     

Dominating motivation in systemic memory mechanisms

The materials provided in the article support the key role of dominating motivation in the systemic processes of fixation and opening of memory mechanisms. The activating mechanisms of dominating motivations in the systemic architectonics of behavioural acts provide the basis for development of a multicomponent acceptor apparatus of an action outcomes broadly represented in various analysing brain sections. As result of enhancement of action outcomes on acceptors structures, molecular behaviour engrammes form within the functional systems. It is these molecular engrammes that are opened by dominating motivations in the same spatial-temporal sequence in which training takes place, and determine deliberate actions of animals. It was demonstrated that dominating motivation opens genetic information with an approximating-exploratory reaction under strong activation of early genes expression, in particular, of c-fos gene protein. Inherent motivation reactions are not blocked by inhibitors of proteins synthesis, by cycloheximide, in particular. In the process of training animals, i.e., satisfaction of the demands which are the basis of dominating motivations, expression of early genes in reduced, while expression of late genes is initiated. In this case, blockators of protein synthesis begin to produce strong inhibiting impact on behaviour of animals.     

Effect of one-time and chronic administration of ethanol on the concentration of beta-endorphin in the brain of rats with different alcoholic motivation

The concentration of beta-endorphin was determined in the cortex of the large hemispheres, thalamus, striatum and medulla oblongata of rats with varying duration of ethanol anesthesia and after a single injection of ethanol (2.5 g/kg). The content of beta-endorphin was also measured in the brain of rats which preferred and rejected 15% ethanol during long-term (up to 10 months) alcoholization. The data obtained indicate that ethanol produces a specific effect on the endorphinergic system in different brain structures of animals predisposed to voluntary alcoholization. A possible involvement of the neuropeptide in the formation of alcohol tolerance and physical dependence is discussed.     

Effect of drugs influencing central serotonergic mechanisms on pentazocine-induced catalepsy in mice

Cataleptic effect of pentazocine in mice was affected by pretreatment with dexfenfluramine, fluoxetine, buspirone, p-chlorophenylalanine, cyproheptadine, mianserin, cisapride, ondansetron, pindolol and propranolol. The results suggest that drugs which influence the activity of central serotonergic systems do modulate pentazocine-induced catalepsy in mice.