Salivary cooling,escape reaction and heat pain in capsaicin-desensitized rats

Salivary thermolytic mechanism (weight of salivary glands, effect of desalivation on water intake and body temperature, grooming activity) as well as escape behaviour and reaction to heat pain were studied in capsaicin-desensitized and control rats exposed to various warm ambient temperatures. Body temperature of the desensitized rats increased more than the controls at all the ambient temperatures studied (32, 34 and 36°C); however, significant differences in the mechanism of salivary cooling were obtained only at 34 and 36°C. Central impairment of saliva spreading in desensitized rats seems evident. Complete surgical desalivation did not increase hyperthermia of control and desensitized animals in warm environments. Therefore other mechanisms, primarily vasodilatatory, must also be involved in the rat's thermolytic normal response. Although desensitized rats did not show a tendency to escape from the warm environment their response to heat pain was normal. In conclusion, it is suggested that heat perception in desensitized animals is impaired; however, the existence of some capsaicin-insensitive thermolytic mechanisms (prone extension of the body) cannot be excluded.Supported by the Scientific Research Council, Ministry of Health, Hungary /4-05-0303-04-2/0/ and MTA-OM-MÉM-EÜM 70.211/79     

Acute effect of phenobarbital on escape behavior

Rats were trained to run in a straight alley to escape shock. Subsequently, phenobarbital was administered and more trials given. Phenobarbital retards running at all doses tested in a curve that is positively accelerating as a function of dose on the first trial. The first trial is markedly slower than later trials with the greatest effect occurring at the higher dosages.     

Learning in escape/avoidance tasks in female rats does not vary with reproductive condition

To determine whether the development of novel stimulus-response associations by the mother during the periparturient period is attributable to a general facilitation of learning produced by the hormonal milieu during that period, learning ability under various reproductive conditions was assessed in two tasks unrelated to the periparturitional situation. The two tasks, selected because they equalized the various groups for motivation and performance variables, were acquisition of a water-maze escape (including two reversals), and acquisition and retention of an unsignalled shuttlebox shock avoidance. The groups tested in the water maze were a midpregnant group, an immediately prepartum group, and an immediately postpartum group. In the shuttlebox, the same conditions (different rats) were compared, together with a nonpregnant estrus condition, and a nonpregnant diestrus condition. The results of both experiments indicate that although learning occurred, the characteristics of acquisition and retention were not influenced by reproductive condition.     

The involvement of an opiate mechanism in the sensitized behavioral deficit induced by early chronic variable stress: influence of desipramine

The influence of early chronic variable stress (CVS) associated with persistent desipramine (DMI) administration was examined on escape performance. Animals were exposed to CVS and 1 day later administered DMI (5 mg/kg, i.p. twice a day) or vehicle (VH) during six consecutive days. Escape performance was assessed over 24 h following inescapable shock (IS) exposure. Higher escape failures were observed in CVS shocked rats compared with unstressed shocked animals. DMI normalized escape failures in both groups. In order to investigate the role of an endogenous opiate mechanism presumably activated by CVS exposure in this behavioral deficit, rats were administered naltrexone (NAL, 2 mg/kg i.p.) or VH prior to each daily stressor of the CVS regime. NAL pretreatment blocked escape failures performed only by CVS shocked rats. In addition, animals were daily administered morphine (MOR, 10 mg/kg, i.p.) or VH during seven consecutive days and subsequently administered DMI. A significant increase in escape deficit in shocked rats was observed after chronic MOR but not following the associated treatment with MOR and DMI. These behavioral data suggest that early experience with a CVS facilitated the onset of escape deficit induced by a brief IS event, an effect that can be prevented by chronic DMI. Furthermore, this sensitized escape deficit response seems to be partially modulated by the previous activation of an opiate mechanism.     

Noradrenergic and dopaminergic interactions in escape behavior: Analysis of uncontrollable stress effects

The effects of norepinephrine receptor blockade on the deficits of escape behavior induced by haloperidol and by inescapable shock were evaluated. Phenoxybenzamine, the -norepinephrine receptor blocker, was found to enhance escape behavior and to eliminate the disruptive effects of both inescapable shock and haloperidol. In contrast, the -norepinephrine receptor antagonist, propranolol, was without effect on behavior under any of these conditions, while the dopamine--hydroxylase inhibitor, FLA-63, disrupted performance. Like phenoxybenzamine, the norepinephrine receptor stimulant, clonidine, was found to eliminate the behavioral disruption produced by haloperidol. These somewhat paradoxical findings were discussed in terms of the contribution of DA-NE interactions in determining behavioral change in aversive paradigms.     

Rats bred for ethanol sensitivity: Impairment of swimming by ethanol and pentobarbital

Rats selectively bred for disparate degrees of ethanol-induced depression of spontaneous locomotor activity (most affected = MA; least affected = LA) were trained on a swim task. Undrugged rats of the MA line swam significantly faster than rats of the LA line. Ethanol, 0.0–2.25 g/kg i.p., produced dose-dependent increases in swim time in rats of the 13th generation (F13). Averaged over trials, these increases were greater in LA than in MA rats and greater in males than in females, but there was no sex difference in peak impairment. Increases in swim time were uncorrelated with predrug performance. These findings were confirmed in younger F17 rats receiving 1.75 g EtOH/kg i.p. Although the lines differed in ethanol-induced impairment, F17 males of the two lines were not differentially impaired by pentobarbital (12.5–22.5 mg/kg, i.p.). The existence of task-dependent line differences in ethanol sensitivity emphasizes the nonunitary nature of ethanol-induced behavioral depression.     

Looking at a predator with the left or right eye: Asymmetry of response in lizards

Studies carried out with the common wall lizard (Podarcis muralis) revealed preferential use of the left eye during responses to predatory threat in laboratory settings and in the wild. Here we tested lizards under monocular conditions of vision, using temporary eye-patching. Lizards were facing a (simulated) predatory threat laterally, from the side of the non-patched eye. Results showed that lizards with the left eye uncovered during predatory threat used the left eye to monitor the predator, whereas lizards with the right eye uncovered nonetheless tried to use the covered left eye. Moreover, lizards frequently tried to change the eye exposition, making a body C-bend behaviour. Right-eyed lizards showed more frequent and faster C-bending responses than left-eyed lizards, trying to monitor the predator with the left eye even though it was patched. Results fit with asymmetries in spontaneous eye use observed in laboratory conditions and in the wild in this species, confirming that structures located on the right side of the brain (mainly served by the left eye) predominantly attend to predatory threat.     

Reduced aggression in mice lacking the serotonin transporter

Abstract Rationale. The possible role of γ-aminobutyric acid (GABA) in human aggression was evaluated by administering baclofen, a GABA-B agonist and comparing the effects on laboratory measures of aggression and escape among subjects with and without a history of conduct disorder. Methods. Twenty male subjects with a history of criminal behavior participated in experimental sessions, which measured aggressive and escape responses. Ten subjects had a history of childhood conduct disorder (CD+) and ten control subjects had no history of CD. Aggression was measured using the point subtraction aggression paradigm (PSAP), which provides subjects with aggressive, escape, and monetary-reinforced response options. Results. Acute doses (0.07, 0.14 and 0.28 mg/kg) of baclofen had remarkably different effects on aggressive responses among CD+ subjects relative to control subjects. Aggressive responses of CD+ subjects decreased, while aggressive responses of control subjects increased following baclofen administration. Baclofen decreased escape responses for both CD+ and control subjects. No changes in monetary-reinforced responses were observed, indicative of no central nervous system stimulation or sedation. Conclusions. The GABA-B agonist baclofen suppressed aggressive responses in subjects with a history of childhood CD, while producing the opposite effect in control subjects. These suggest a possible unique role for GABA in the regulation of aggression in CD+ population. Electronic Publication     

人乳腺珠蛋白与乳腺癌

人乳腺珠蛋白(hMAM)是乳腺组织特异性表达的分泌性蛋白,目前被认为是一种具有临床应用前景的乳腺肿瘤标志物。现就MAM在乳腺癌肿瘤免疫治疗中的应用、作为乳腺癌肿瘤标志物的诊断现状和存在问题等方面探讨MAM在乳腺癌肿瘤疫苗的设计、诊断及转移检测的作用。     

Air and shock two-way shuttlebox avoidance in C57BL/6J and 129X1/SvJ mice

Despite multiple advantages of the use of electric shock as an aversive stimulus, reasons exist for considering alternative aversive stimuli. In the present study, we examined and compared the acquisition of two-way shuttlebox avoidance with 275.8-kPa (40-psi) pulsed air and continuous 0.4-mA shock in two strains of mice commonly employed in targeted gene mutation research, C57BL/6J and 129X1/SvJ. Each trial consisted of a 5-s warning stimulus (WS, light) during which shuttling to the other side cancelled delivery of the aversive stimulus. Once initiated, the aversive stimulus remained active for 20 s or until an escape response occurred. For C57BL/6J mice, air and shock were equally and highly effective aversive stimuli. In contrast, air was less effective than shock for 129X1/SvJ mice. C57BL/6J mice outperformed 129X1/SvJ mice for both stimulus types. For 129X1/SvJ mice, longer escape latencies were observed initially for air, suggesting that shock is more effective. However, these differences in latency dissipated within the first seven sessions. Nevertheless, by the end of the 17-day study, asymptotic levels of avoidance proficiency were substantially lower for air than for shock in 129X1/SvJ mice. These results indicate that air is a suitable substitute for shock as an aversive stimulus in shuttlebox active avoidance; however, the relative efficacies of these aversive stimuli appear to depend upon the strain chosen for study.