Reciprocal Balance Research Articles

Rac downregulates Rho activity: reciprocal balance between both GTPases determines cellular morphology and migratory behavior.

Using biochemical assays to determine the activation state of Rho-like GTPases, we show that the guanine nucleotide exchange factor Tiam1 functions as a specific activator of Rac but not Cdc42 or Rho in NIH3T3 fibroblasts. Activation of Rac by Tiam1 induces an epithelial-like morphology with functional cadherin-based adhesions and inhibits migration of fibroblasts. This epithelial phenotype is characterized by Rac-mediated effects on Rho activity. Transient PDGF-induced as well as sustained Rac activation by Tiam1 or V12Rac downregulate Rho activity. We found that Cdc42 also downregulates Rho activity. Neither V14Rho or N19Rho affects Rac activity, suggesting unidirectional signaling from Rac towards Rho. Downregulation of Rho activity occurs independently of Rac- induced cytoskeletal changes and cell spreading. Moreover, Rac effector mutants that are defective in mediating cytoskeleton changes or Jun kinase activation both downregulate Rho activity, suggesting that neither of these Rac signaling pathways are involved in the regulation of Rho. Restoration of Rho activity in Tiam1-expressing cells by expression of V14Rho results in reversion of the epithelioid phenotype towards a migratory, fibroblastoid morphology. We conclude that Rac signaling is able to antagonize Rho activity directly at the GTPase level, and that the reciprocal balance between Rac and Rho activity determines cellular morphology and migratory behavior in NIH3T3 fibroblasts.

Effects of repeated treatment with methamphetamine plus scopolamine and methamphetamine on behavioral sensitization and conditioning

This study compared repeated treatment with methamphetamine (4.0 mg/kg, i.p.) plus scopolamine (0.5 mg/kg, i.p.) and methamphetamine alone in behavioral sensitization and drug conditioning with respect to a reciprocal balance between the dopaminergic and cholinergic systems. Repeated methamphetamine plus scopolamine treatment induced a more progressive and enduring enhancement of stereotyped behavior than repeated methamphetamine treatment. Methamphetamine plus scopolamine-induced stereotyped behavior was reproduced by challenge injections of not only methamphetamine plus scopolamine and methamphetamine, but also, to a lesser extent, by scopolamine challenges. The methamphetamine plus scopolamine-sensitized rats were conditioned to a low-frequency tone (300 Hz, 100 dB) as conditioned stimulus associated with the drug state. They responded to pairings of the tone and placebo injections, but not to the tone alone or the placebo alone. The methamphetamine-sensitized rats failed to exhibit conditioning. These results suggest that methamphetamine plus scopolamine-induced pronounced behavioral sensitization may produce an enhanced conditioning. Exteroceptive conditioned stimulus-interoceptive unconditioned stimulus associations may provide an important source for drug conditioning. We concluded that behavioral sensitization may be mediated via a reciprocal balance between the dopaminergic and cholinergic systems, in favor of a dopaminergic dominance. Conditioning to the drug-associated tone may operate via a reciprocal balance between the dopaminergic and cholinergic systems.

A brief history of balance through time

We present methods for establishing the amount of reciprocity, transitivity and group balance (a generalization of structural balance) in sociometric structures. These methods are applied to the second time series of sociometric data provided by the Newcomb (1961) study. The amount of reciprocity was above chance levels at the outset and showed no systematic variation thereafter. Transitivity has a very different time scale. It climbed steadily through the first nine weeks and remained stable thereafter. While consistent with chance at the beginning of the study period, it grew to above chance levels at week 3. Group imbalance declined throughout the entire period. The reasons for these different time scales are discussed.

Behavioral responses induced by repeated treatment with methamphetamine alone and in combination with scopolamine in rats.

Repeated amphetamine (A) or methamphetamine (M) treatment induces behavioral sensitization and drug conditioning. The present study compared behavioral sensitization and drug conditioning between treatments with M combined with scopolamine (S) and M alone with respect to a reciprocal balance between the dopaminergic and inhibitory cholinergic systems in rats. Repeated treatment with M (4.0 mg/kg i.p.) combined with S (0.5 mg/kg i.p.) (MS) produced progressive enhancement of stereotyped behavior, compared with repeated M treatment alone. Repeated MS treatment induced focussed stereotyped behavior that was elicited by every challenge injection of not only MS and M, but also partially by S. MS- but not M-sensitized rats exhibited conditioned responses to a tone (300 Hz, 100 dB) associated with drug state, suggesting that MS-induced pronounced behavioral sensitization may lead to an enhanced conditioned response to the conditioned stimulus (CS) of a tone. It is suggested that MS-induced behavioral sensitization may be mediated via a reciprocal balance between the dopaminergic and cholinergic systems in favor of a dopaminergic dominance, and that such a balance may be involved in the conditioning to the drug-associated tone CS.

Methamphetamine plus scopolamine potentiates behavioral sensitization and conditioning

The effects of repeated methamphetamine (4.0 mg/kg) plus scopolamine (0.5 mg/kg) treatment on behavioral sensitization and drug conditioning in rats were compared with the effects of repeated methamphetamine treatment. Behavioral sensitization induced by repeated methamphetamine plus scopolamine treatment was more vigorous than that induced by repeated methamphetamine treatment. Repeated methamphetamine plus scopolamine treatment produced sensitized responses, not only to methamphetamine plus scopolamine and methamphetamine but also, to a lesser extent, to scopolamine. Methamphetamine plus scopolamine-sensitized rats but not methamphetamine-sensitized rats exhibited conditioned responses to a low-frequency tone (300 Hz, 100 dB) associated with the drug state, suggesting that robust methamphetamine plus scopolamine-induced behavioral sensitization may lead to enhanced conditioning. It is plausible that robust behavioral sensitization might operate via a reciprocal balance between the dopaminergic and cholinergic systems in favor of dopaminergic dominance. Conditioning to the drug-associated tone may be mediated via a reciprocal balance between the two transmitter systems.

Cooperation and competition in the industrial district as an organization model

Abstract Starting from the theory of the industrial district, this paper concentrates on the interplay between competition and cooperation characteristic of the industrial district as an organization model. After recalling the wide vertical and horizontal division of labour between firms in the district, it is shown how cooperation based on local custom and investments in personal reputation allows for the coordination of a large part of complementary activities carried out by local independent firms. Subsequently, we see how competition between firms and agents specialized in similar activities drives them towards allocative efficiency and innovation. Finally, the paper focuses on the reciprocal balance between cooperation and competition which is necessary for stability over time in the industrial district.

Reciprocal unconditional-conditional organization of the fundamental emotions and paraadaptive personality reactions.

Paraadaptive personality reactions (PPR) are modes of behavior and experience on the borderline of normal psychology and psychopathology. In them the thinking is overdetermined or obsessive. Overdetermined PPR are well illustrated in common proverbs. The people's wisdom has also knowledge of the obsessive (or "magic") paraadaptive rituals for prevention of possible misfortunes (such as touching wood, keeping away from a black cat, etc.). One part of the PPR is described in the psychoanalytical literature as defense mechanisms. The analysis of thought dissociation in schizophrenia shows that the reciprocal relations could be considered as a basic principle of functional organization on all levels of nervous and psychic activity. Proceeding from this assumption, the author proposes the conception of a reciprocal neuropsychological unconditional-conditional affect-behavioral system (ABS). It consists of ten subsystems corresponding to the basic emotions. Each subsystem stimulates the personality toward predetermined forms of thinking and behavior. In adequate conditions the reciprocal processes in the ABS are well counterweighted and integrated. In some persons and in situations of greater affective "loading" this reciprocal balance is disorganized, which leads to PPR. In this paper a neuropsychological analysis is made of the overdetermined PPR, reflected in such proverbs as "Not being able to beat the donkey, he beats the packsaddle" and "The thief cries catch the thief."

The Humoral Renal Antihypertensive System: Nervous and Hemodynamic Effects in Normotensive and Undipped Renal Hypertensive Rats

A series of studies of the humoral renal antihypertensive system in normotensive and 2K 1C-renal antihypertensive rats is outlined. The rapid structural upward resetting of the cardiovascular system in renal hypertensive rats was associated with a structural downward resetting in the vasculature of the hypotensive clipped kidney. Unclipping of this kidney caused a pronounced release of renomedullary depressor agents, explaining the rapid normalization of pressure seen after unclipping. This normalization of pressure masks a state of pronounced functional hypotension in a structurally still hypertensive cardiovascular system, characterized by marked splanchnic vasodilatation and a lack of neurogenic counter-regulation. Only when this state has lasted long enough to normalize the structural upward resettings, characteristic of hypertension does the cardiovascular system return to normal. Further, cross-circulation techniques have shown that the humoral antihypertensive agents suppress tonic sympathetic activity, thereby inhibiting normal reflex counter-regulation of their vasodilator effects. Presumably this occurs via both vagal cardiac afferents and central actions. Further, behavior and awareness become depressed during intense and prolonged renomedullary release. Finally, experiments for which a normotensive kidney is cross-circulated from a normotensive rat suggest that the humoral renomedullary antihypertensive system has its threshold of release set so low as to contribute to normal blood pressure regulation, presumably in reciprocal balance with the renocortical renin-angiotensin system. Stepwise pressure elevations increasingly enhance release of the depressor agents from the cross-perfused kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurements of plasma levels of adrenergic neurotransmitters and primary amino acids in five stuttering subjects: A preliminary report (biochemical aspects of stuttering)

The present study measured plasma levels of epinephrine, norepinephrine, dopamine, and primary amino acids of five stutters employing state-of-the-art high performance liquid chromatographic technology. Pertinent findings showed that glutamine levels of all five subjects were more than four standard deviation units higher than the reference mean, which was interpreted as reflecting a possible increase in left hemispheric GABAergic activity When considered within the parameters of a reciprocal interhemispheric neurotransmitter balance theory, such findings may well suggest that neurotransmitter ratios between and within the two hemispheres are aberrant in the stuttering population. A theoretical model is presented elucidating these disturbed relationships and their possible influence on speech fluency.

Cognitive Balance and Differential Popularity in Social Networks

That cognitive balance is not the only possible explanation for transitivity in sentiment networks is hardly a matter of debate. At least five substantive explanations for transitivity can be provided: tendencies toward friendliness (expansiveness), reciprocity, differential popularity, clustering, and cognitive balance. A number of studies over the past decade have focused on one or more of these social processes and their relationships to transitivity. In an early paper, Hallinan and S0rensen (1973) show how the amount of intransitivity in a graph is greatly reduced when tendencies toward hierarchy (differential popularity) and mutuality (reciprocity) are controlled for. In a later paper, S0rensen and Hallinan (1976) demonstrate how the avoidance of intransitive triads impedes the process of clustering in a network. Davis (1977) shows that individual differences in choice relations can account for a considerable amount of transitivity. Holland and Leinhardt (1979) describe random baseline models that control for various structural factors that may affect the incidence of transitivity in a sociogram. More recently, Echterhagen et al. (1981) have presented results from a set of simulations that illustrate convincingly that transitivity increases with density (clustering) and as the number of indegrees (differential popularity) in a graph increases. Since Feld and Elmore's work lies in this tradition, their basic premise is neither new nor disputable. They attempt to show how differential popularity can account for some of the empirically observed transitivity in social networks. There are problems in each of Feld and Elmore's three empirical analyses aimed at demonstrating the presence of inequality in a sociogram and comparing cognitive balance and differential popularity explanations of transitivity. These problems include their use of: (1) an incorrect baseline to illustrate the presence of inequality in sociometric data; (2) incorrect expected values to compare the fre-

Competitive displacement ofAnagyrus antoninae [Hym.: Encyrtidae]. by its ecological homologueNeodusmetia sangwani [Hym.: Encyrtidae

The displacement ofAnagyrus antoniaaeTimberlake byNeodusmetia sangwani (Rao) was demonstrated by reduced parasitism by the former in two localities after the latter was introduced into these sites. The competitive factors were: (1) the host-regulative action ofN. sangwani maintained a low host reciprocal balance, and (2) the inability of the female ofA. antoninae at the prevailing host density to find hosts sufficient for reproduction. The lack of competitiveness ofA. antoninae was a result of its inability to develop at high vapor deficits.

Influence of pheniramine and chlorpheniramine on apomorphine induced compulsive gnawing in mice.

In mice, apomorphine (10 mg/kg s.c.) does not induce a compulsion to gnaw, but pretreatment with antihistamines, viz. pheniramine, chlorpheniramine and mepyramine, in doses ranging from 30 to 60 mg/kg i.p. caused gnawing activity. Mepyramine showed significantly less effect when compared to the other two agents. Antihistamines are known to influence the activity of biogenic amines in central nervous system. The potentiation of apomorphine-induced gnawing by antihistamines might depend upon the reciprocal balance between dopaminergic and cholinergic systems. This was tested by blocking biosynthesis of biogenic amines or by blocking their receptors. The potentiation of gnawing was antagonised by physostigmine (0.25 mg/kg) or blocked by pretreatment with alpha-methyl-p-tyrosine (alpha-MPT) (4 X 150 mg/kg) and bis-(4-methyl-1-homopiperazinylthiocarbonyl)-disulphide (FLA) (40 mg/kg), while p-chlorophenyl alanine (p-CPA) (3 X 100 mg/kg) had no effect. Similarly, phenoxybenzamine (30 mg/kg) and haloperidol (1.0 mg/kg) inhibited gnawing activity, but methysergide (10 mg/kg) had no effect. Furthermore, pretreatment with tetrabenazine (20 mg/kg) and L-Dopa (200 mg/kg) did not affect gnawing activity. It is concluded that both pheniramine and chlorpheniramine potentiate apomorphine gnawing by upsetting the cholinergic and dopaminergic balance in favour of dopaminergic dominance.

Modification of amphetamine effects by intracerebrally administered anticholinergic agents

The present work, using a combination of peripheral and central injection techniques, was designed to investigate the postulate that cholinergic systems in the basal ganglia are important in the control of amphetamine stereotypy and, further, that this control is mediated via a reciprocal balance with dopaminergic systems in the same brain area. The intensity of stereotyped behaviour observed after peripherally administered amphetamine was increased immediately following the injection of orphenadrine into either the striatum or globus pallidus. However, similar intracerebral injections of atropine and phenglutarimide only potentiated amphetamine stereotypy after a latency of at least 30 mins., during which time the intensity of stereotypy was markedly reduced. It would therefore appear that cholinergic mechanisms in both the striatum and pallidum are involved in the control of amphetamine stereotypy, but that the nature of this control may not be as simple as may be explained in terms of a reciprocal balance with dopaminergic systems in the same brain areas. The possibility is discussed that actions of drugs other than are observed after peripheral administration may be apparent when the drugs are applied directly on to neuronal tissue.

FIBROUS STRUCTURE OF THE TYMPANIC MEMBRANE IN VERTEBRATES

The author examined the fibrous structure of the tympanic membrane in amphibians, reptiles, birds and mammals under the microscope with a polaroid attachment. The conclusions were as follows: 1) The lamina propria of the tympanic membrane was composed of two groups of fibers, radial and non-radial. The radial fibers, could be found in all of the examined vertebrates. On the other hand, the non-radial fibers could be found in 'all vertebrates except some amphibians (Fig. 1). The arrangement of the non-radial fibers varied in different species, but had resemblance in a same species (Fig. 1∼10). 2) In mammals, the non-radial fibers consist of three sub-groups, circular, parabolic and trans- versal: The circular fibers could be divided into two types. In typeI, fibers ran in parallel with each other, while in typeII, fibers ran across to make network (Fig. 7, 14, 18). The mixture of those two types of arrangement of fibers was not observed. The parabolic fibers originated from the short process of the malleus and ran in parabolic courses forward and backward to the periphery of the tympanic membrane. The fibers which were discovered in certain mammals in this study, were designated as the transversal fiber by the author. These fibers ran from one point in the periphery of the tympanic membrane to an opposite in the inferior area of the membrane, making arches with their concavity against the umbo (Fig. 9, 10, 20). 3) Secondi and Fumagalli discovered the fiber at the border of the tympanic membrane in some mammals. The crescentic fibers and the parabolic fibers were mentioned to make the parabolic-crescentic (Fig. 11). Moreover, they mentioned that this system and the radial fibers were in a reciprocal balance, and with different position of the malleus, the degree of their bending would change, but not their tension. However, in this study the so-called fiber were not observed. Although small arches of fibers were regarded as the crescentic fibers at the border of the membranes in some mammals (ape and mankind), those fibers were confirmed to be the endings of the parabolic fib ers by the author (Fig.12, Fig.19, d). This indicates that the parabolic fibers transmit the acoustic vibration of the tympanic membrane to the short process of the malleus concentrically (Fig. 13). 4) According to the morophological observations above mentioned, the author assumed that the difference in the mode of vibration of the tympanic membrane depended upon the difference in the structure of the fibers of the tympanic membrane. This assumption was assertained in this study by means of a stroboscope (Fig. 15, 16).

The relationship of tachycardia to cardiac insufficiency

The various elements of the circulation are subject to reflex variation. By reciprocal adjustments balance tends to be maintained despite disorder in one component. Primary impairment of the peripheral circulation or of cardiac output produces reflex acceleration of sinus heart rate. Compensatory tachycardia is physiological, not harmful. Its primary abatement is not a proper therapeutic objective. Improvement is followed by reverse slowing. Conversely, primary acceleration of rate tends to induce compensatory adjustment in blood pressure, and in systolic discharge. With sinus rates nearly as high as 200, the circulation remains adequate. Abnormal rhythms are not subject to reflex compensatory adjustment in rate. Certain special features, also, may affect the circulation adversely. In auricular fibrillation the ventricular rate appears to depend largely upon the state of the ventricular muscle. This arrhythmia frequently occurs in congestive heart failure. Under such circumstances reduction in rate follows improvement in the muscle, from digitalis or from other cause. In cases of fibrillation without heart failure the muscular effect of digitalis is not beneficial; in such instances administration of the drug is not followed by slowing. In auricular fibrillation, as in normal rhythm, abatement of tachycardia appears not to be the cause of improvement but to be the result of it.