[Psychological Impact of COVID-19 on Health Workers During the Second Year of the Pandemic in Latin America: Cross-Sectional Survey Study]

Introduction

The coronavirus pandemic continues to affect the mental health of healthcare personnel in Latin America (LA).

Objective

To estimate the prevalence of psychological disturbances and associated risk factors for mental health in healthcare personnel in LA during the second year of the COVID-19 pandemic.

Method

This multicenter cross-sectional study included a total sample of 5437 healthcare professionals from Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. The PHQ-9, GAD-7, and a brief demographic questionnaire were used. The prevalence of anxiety and depression was estimated based on the cut-off points of the instruments. Two multivariate logistic regressions were performed.

Results

A population burden of anxiety (40.1%) and depression (62.2%) was found in healthcare personnel in LA. Among professionals in Argentina (OR = 1.374; P<.001), those working in state hospitals (OR = 1.536; P<.003), frontline healthcare workers for COVID patients (OR = 1.848; P<.001), general practitioners (OR = 1.335; P<.001), and specialists (OR = 1.298; P<.001), a higher risk of experiencing mental disorders was observed. Among women, younger personnel, and administrative staff, a higher probability of experiencing anxiety and depression was identified.

Conclusions

The burden of mental disorders on healthcare personnel in Latin America is alarming. Psychological support services are necessary, aimed at providing measures for professionals to develop healthy coping mechanisms that mitigate the impact of the pandemic on their well-being and facilitate post-crisis adjustment.

The role of ketamine in major depressive disorders: Effects on parvalbumin-positive interneurons in hippocampus

Major depressive disorder (MDD) is a complex illness that is arising as a growing public health concern. Although several brain areas are related to this type of disorders, at the cellular level, the parvalbumin-positive cells of the hippocampus interplay a very relevant role. They control pyramidal cell bursts, neuronal networks, basic microcircuit functions, and other complex neuronal tasks involved in mood disorders. In resistant depressions, the efficacy of current antidepressant treatments drops dramatically, so the new rapid-acting antidepressants (RAADs) are being postulated as novel treatments. Ketamine at subanesthetic doses and its derivative metabolites have been proposed as RAADs due to their rapid and sustained action by blocking N-methyl-d-aspartate (NMDA) receptors, which in turn lead to the release of brain-derived neurotrophic factor (BDNF). This mechanism produces a rapid plasticity activation mediated by neurotransmitter homeostasis, synapse recovery, and increased dendritic spines and therefore, it is a promising therapeutic approach to improve cognitive symptoms in MDD.

[Prevalence and factors associated with subjective cognitive complaints in Latin American health workers during the COVID-19 pandemic]

Background and objectives: An increase in emotional disturbances and complaints about cognitive performance has been observed in Latin American healthcare workers during the SARS-CoV-2 pandemic, which can affect attention capacity and increase the levels of stress and burnout of these professionals. The objective was to analyse subjective cognitive complaints (SCC) and associated factors in health personnel during the COVID-19 pandemic in five Latin American countries.Methods: Multicentre cross-sectional study, which included 3,738 professionals from Colombia, Chile, Argentina, Ecuador, Bolivia, and Peru. The Generalized Anxiety Disorder Scale (GAD-7) and the Patient Health Questionnaire (PHQ-9) was used to assess depression, and the Mini-Z to assess Burnout. For the SCC, an item on cognitive concerns in attention and memory was used.Results: The prevalence of cognitive complaints was 69.2%. The factors associated with a higher risk of SCC were the scores in the GAD-7, PHQ and Mini-Z, in addition to being part of the Ecuadorian health personnel.Conclusions: There is a high prevalence of SCC in health personnel, which is modulated by emotional states and stress.

Acute Thalamic Ischemic Stroke in an Older Patient Newly Vaccinated with COVID-19 Vaccine Based on Adenoviral Vectors

INTRODUCTION

Recent reports have shown several cases of cerebrovascular events after vaccination against COVID-19. The effects have been described mainly in women within the first two weeks of receiving the vaccine.

CLINICAL CASE

We describe here the first Colombian case of a cerebrovascular event after vaccination against COVID-19 in a 67-year-old woman with a vascular history. Four days after application of the messenger ribonucleic acid (mRNA) vaccine, she exhibited deviation of the labial commissure, ipsilateral ptosis, and limitation of march with lateralization. The event was associated with a subacute ischemic event in the right thalamus in parasagittal situation, changes in chronic ischemic microangiopathy of small vessels, and vascular crossing in the right cerebellar angle, without other alternative causes.

CONCLUSION

The development and rapid use of vaccines has allowed the hospitalization and mortality statistics associated with COVID-19 to be reduced, but at the same time, it has generated concern about the potential side effects, generating controversy among the general population, especially in individuals with cardiovascular diseases. In our case, we provided evidence for the discussion of potential cerebrovascular events related to the application of vaccines in older people with a history of cerebrovascular diseases. This was done in order to analyze and control in subsequent studies the modulation of medical history on the likely effects of vaccination. However, despite the unavoidable side effects, the benefits of vaccination are superior.

The maintained attention assessment in patients affected by Myalgic encephalomyelitis/chronic fatigue syndrome: a reliable biomarker?

The maintained attention is the cause of great functional limitations in CFS/ME, a disease that mainly affects women in the central period of life. Cognitive function is explored using the Montreal Cognitive Assessment, the maintained attention using the Toulouse-Piéron test with which the Global Index of Attention and Perception (GIAP) is obtained, the fatigue using the visual analog scale and the perception of effort using the modified Borg scale. The final sample were 84 patients (66 women/18 men) who met diagnostic criteria (Fukuda-1994, Carruthers-2011) and 22 healthy controls (14 women/8 men). Most of patients maintain normal cognitive function, showing low or very low attention score in the 70% of patients with a marked cognitive fatigue compared to the control group (p < 0.05). There were no significant differences between genders in GIAP or fatigue for CFS/ME; however, sick women perceive cognitive effort higher than men. Deficits in sustained attention and the perception of fatigue, so effort after performing the proposed test are a sensitive and reliable indicator that allows us to substantiate a clinical suspicion and refer patients for further studies in order to confirm or rule out CFS/ME.

Clinical Heterogeneity in ME/CFS. A Way to Understand Long-COVID19 Fatigue

The aim of present paper is to identify clinical phenotypes in a cohort of patients affected of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Ninety-one patients and 22 healthy controls were studied with the following questionnaires, in addition to medical history: visual analogical scale for fatigue and pain, DePaul questionnaire (post-exertional malaise, immune, neuroendocrine), Pittsburgh sleep quality index, COMPASS-31 (dysautonomia), Montreal cognitive assessment, Toulouse-Piéron test (attention), Hospital Anxiety and Depression test and Karnofsky scale. Co-morbidities and drugs-intake were also recorded. A hierarchical clustering with clinical results was performed. Final study group was made up of 84 patients, mean age 44.41 ± 9.37 years (66 female/18 male) and 22 controls, mean age 45 ± 13.15 years (14 female/8 male). Patients meet diagnostic criteria of Fukuda-1994 and Carruthers-2011. Clustering analysis identify five phenotypes. Two groups without fibromyalgia were differentiated by various levels of anxiety and depression (13 and 20 patients). The other three groups present fibromyalgia plus a patient without it, but with high scores in pain scale, they were segregated by prevalence of dysautonomia (17), neuroendocrine (15), and immunological affectation (19). Regarding gender, women showed higher scores than men in cognition, pain level and depressive syndrome. Mathematical tools are a suitable approach to objectify some elusive features in order to understand the syndrome. Clustering unveils phenotypes combining fibromyalgia with varying degrees of dysautonomia, neuroendocrine or immune features and absence of fibromyalgia with high or low levels of anxiety-depression. There is no a specific phenotype for women or men.

Effects of atenolol injected into the nucleus accumbens septi in rats in the elevated plus-maze test

Background In previous studies, we have observed that glutamate antagonists injected within the nucleus accumbens septi (NAS) induced an anxiolytic-like effect in the elevated plus maze (EPM) test in rats. In the present study, the effect of Atenolol, a specific Beta Adreno-receptor antagonist in the EPM was studied in male rats bilaterally cannulated NAS. Methods Rats were divided into five groups that received either 1 μL injections of saline or atenolol in different doses (0.75, 1 or 2 μg/1 μL, n=15-16) 15 min before testing. Results Time Spent in the Open Arm was modified by treatment (F=4.563, p=0.006, df 3). This was increased by the lowest dose of atenolol (p<0.05), by the medium doses (p<0.001) and also by the highest dose (p<0.01). Time per Entry was modified by treatment (F=4.54, p=0.06, df 3). This parameter was increased by the lowest dose of atenolol (p<0.01), but not for the medium and higher doses. Conclusions We conclude that Atenolol beta receptor blockade in the accumbens lead to an anxiolytic-like effect related to an increase in the time spent in the open arm and in the time per entry, showing specific behavioral patterns.

Effects of dizocilpine-induced glutamatergic blockade in the nucleus accumbens septi on the plus maze test

BACKGROUND

In previous studies, we have observed that specific N-methyl-d-aspartic acid (NMDA) antagonists and non-NMDA antagonists injected within the nucleus accumbens septi (NAS) induced an anxiolytic-like effect in the plus maze test in rats. In the present study, the effect of intracanalicular blockade of NMDA receptors using dizocilpine in the plus maze was studied in male rats bilaterally cannulated NAS.

METHODS

Rats were divided into five groups that received either 1 μL injections of saline or dizocilpine (MK-801, [5R,10S]-[+]-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine) in different doses (0.5, 1, 2, or 4 μg) 15 min before testing.

RESULTS

Time spent in the open arm increased under dizocilpine treatment with the two higher doses (2 and 4 μg, p<0.05), extreme arrivals were increased by the three higher doses (1 μg, p<0.05; 2 and 4 μg, p<0.01), and open arm entries by the three higher doses (1, 2, and 4 μg, p<0.05). A dose-effect relationship was observed in all cases.

CONCLUSIONS

We conclude that dizocilpine-glutamatergic blockade in the accumbens lead to an anxiolytic-like effect and a behavioral disinhibition related to an increase in some motoric parameters, showing specific behavioral patterns.

Negative transfer effects between reference memory and working memory training in the water maze in C57BL/6 mice

The water maze is one of the most widely employed spatial learning paradigms in the cognitive profiling of genetically modified mice. Oftentimes, tests of reference memory (RM) and working memory (WM) in the water maze are sequentially evaluated in the same animals. However, critical difference in the rules governing efficient escape from the water between WM and RM tests is expected to promote the adoption of incompatible mnemonic or navigational strategies. Hence, performance in a given test is likely poorer if it follows the other test instead of being conducted first. Yet, the presence of such negative transfer effects (or proactive interference) between WM and RM training in the water maze is often overlooked in the literature. To gauge whether this constitutes a serious concern, the present study determined empirically the magnitude, persistence, and directionality of the transfer effect in wild-type C57BL/6 mice. We contrasted the order of tests between two cohorts of mice. Performance between the two cohorts in the WM and RM tests were then separately compared. We showed that prior training of either test significantly reduced performance in the subsequent one. The statistical effect sizes in both directions were moderate to large. Although extended training could overcome the deficit, it could re-emerge later albeit in a more transient fashion. Whenever RM and WM water maze tests are conducted sequentially in the same animals - regardless of the test order, extra caution is necessary when interpreting the outcomes in the second test. Counterbalancing test orders between animals is recommended.

Effects of antidepressants and soybean association in depressive menopausal women

Depression in menopausal women has been widely described for many years ago and is related to hormonal decrease, mainly estrogens. The use of soy has been proposed as a possible coadjutant alternative to treat menopausal depressive disorder. In the present pilot clinical trial the effect of soybean, antidepressants and the association of soybean with antidepressants was studied in 40 depressive menopausal women for three months. Patients were divided in four groups of 10 women: fluoxetine (10 mg), soybean (100 mg), sertraline (50 mg), and sertraline (50 mg) plus soybean (100 mg). The Hamilton and Zung Depression Scales were used to measure the treatment effects. Values at the beginning and at the end of the study were compared. In all cases a significant difference was observed when the treated groups were compared vs. their untreated situation in both scales (p < 0.001). When a comparison between pre- minus post-treatment Zung scale scores was done, the effect induced by the association of sertraline and soybean was significantly higher than the other groups (p < 0.05). These effects were also seen using the Hamilton scale scores, showing significant differences between the association vs. soybean (p < 0.05) and setraline (p < 0.05) groups, but not vs. fluoxetine group. We conclude that soybean has an antidepressant effect per se, and the association of soybean and antidepressants increases their effects.

Intact working memory in the absence of forebrain neuronal glycine transporter 1

Glycine transporter 1 (GlyT1) is a potential pharmacological target to ameliorate memory deficits attributable to N-methyl-d-aspartate receptor (NMDAR) hypofunction. Disruption of glycine-reuptake near excitatory synapses is expected to enhance NMDAR function by increasing glycine-B site occupancy. Genetic models with conditional GlyT1 deletion restricted to forebrain neurons have yielded several promising promnesic effects, yet its impact on working memory function remains essentially unanswered because the previous attempt had yielded un-interpretable outcomes. The present study clarified this important outstanding lacuna using a within-subject multi-test approach. Here, a consistent lack of effects was convincingly demonstrated across three working memory tests - the radial arm maze, the cheeseboard maze, and the water maze. These null outcomes contrasted with the phenotype of enhanced working memory performance seen in mutant mice with GlyT1 deletion extended to cortical/hippocampal glial cells. It follows that glial-based GlyT1 might be more closely linked to the modulation of working memory function, and raises the possibility that neuronal and glial GlyT1 may regulate cognitive functions via dissociable mechanisms.

Glutamatergic ionotropic blockade within accumbens disrupts working memory and might alter the endocytic machinery in rat accumbens and prefrontal cortex

Effects of blocking N-methyl-D-aspartic acid (NMDA) and non-NMDA glutamatergic receptors on performance in the hole board test was studied in male rats bilaterally cannulated into the nucleus accumbens (Acc). Rats, divided into 5 groups, received either 1 microl injections of saline, (+/-) 2-amino-7-phosphonoheptanoic acid (AP-7) (0.5 or 1 microg) or 2,3-dioxo-6-nitro-1,2,3,4,tetrahydrobenzo-(f)quinoxaline-7-sulphonamide disodium (NBQX, 0.5 or 1 microg) 10 min before testing. An increase by AP-7 was observed in ambulatory movements (0.5 microg; p < 0.05), non-ambulatory movements and number of movements (1 microg; p < 0.05); sniffing and total exploration (1 microg; p < 0.01). When holes were considered in order from the first to the fifth by the number of explorations, the most visited holes (first and second) of the AP-7 group were significantly higher than the corresponding holes of saline group (p < 0.05 for 0.5 microg and p < 0.001 for 1 microg). When the second hole was compared with the first of his group, a difference was only observed in the AP-7 1 microg group (p < 0.001). Increasing differences between the other holes and the first were observed by drug treatment. At molecular level, it was observed that AP-7 induced an increase of the coat protein AP-2 expression in Acc, but not AP-180 neither the synaptic protein synaptophysin. The increase of AP-2 was also observed in the medial prefrontal cortex by the action of AP-7 but not NBQX. We conclude that NMDA glutamatergic blockade might induce an activation of the endocytic machinery into the Acc, leading to stereotypies and perseverations, lacking cortical intentional direction.

Prazosin blocks the glutamatergic effects of N-methyl-D-aspartic acid on lordosis behavior and luteinizing hormone secretion in the estrogen-primed female rat

We have observed that intracerebroventricular (icv) injection of selective N-methyl-D-aspartic acid (NMDA)-type glutamatergic receptor antagonists inhibits lordosis in ovariectomized (OVX), estrogen-primed rats receiving progesterone or luteinizing hormone-releasing hormone (LHRH). When NMDA was injected into OVX estrogen-primed rats, it induced a significant increase in lordosis. The interaction between LHRH and glutamate was previously explored by us and another groups. The noradrenergic systems have a functional role in the regulation of LHRH release. The purpose of the present study was to explore the interaction between glutamatergic and noradrenergic transmission. The action of prazosin, an alpha1- and alpha2b-noradrenergic antagonist, was studied here by injecting it icv (1.75 and 3.5 microg/6 microL) prior to NMDA administration (1 microg/2 microL) in OVX estrogen-primed Sprague-Dawley rats (240-270 g). Rats manually restrained were injected over a period of 2 min, and tested 1.5 h later. The enhancing effect induced by NMDA on the lordosis/mount ratio at high doses (67.06 +/- 3.28, N = 28) when compared to saline controls (6 and 2 microL, 16.59 +/- 3.20, N = 27) was abolished by prazosin administration (17.04 +/- 5.52, N = 17, and 9.33 +/- 3.21, N = 20, P < 0.001 for both doses). Plasma LH levels decreased significantly only with the higher dose of prazosin (1.99 +/- 0.24 ng/mL, N = 18, compared to saline-NMDA effect, 5.96 +/- 2.01 ng/mL, N = 13, P < 0.05). Behavioral effects seem to be more sensitive to the alpha-blockade than hormonal effects. These findings strongly suggest that the facilitatory effects of NMDA on both lordosis and LH secretion in this model are mediated by alpha-noradrenergic transmission.

Cognitive effects of dopaminergic and glutamatergic blockade in nucleus accumbens in pigeons

In earlier studies it was found that glutamatergic transmission within the nucleus accumbens septi is involved in the performance of a learned visual shape discrimination in pigeons. This study examines what effects several kinds of glutamate and dopamine antagonists have on the same task. Pigeons were trained with the relevant discrimination, bilaterally implanted with cannulas into the nucleus accumbens and tested after various transmission blockers had been administered intracerebrally. SCH-23390, a D1 dopamine antagonist, at the dose used, had no effect, and Spiperone, a D2-dopamine and 5HT2a-serotonine antagonist, significantly decreased the error repeat trials. CNQX, a non-NMDA glutamate receptor antagonist, and Cycloleucine, an antagonist of the glycine allosteric site of NMDA receptors, had no effect. CGS-19755, a selective competitive NMDA antagonist, significantly impaired performance by significantly decreasing the percent correct trials and increasing the error repeat trials. CPPG, a II/III metabotropic glutamate antagonist, remarkably improved performance. MMPG, a III/II metabotropic glutamate antagonist, at the dose used, did not have any significant effect. The preparation employed may be a useful animal model of perceptual disturbances in schizophrenia.

[Experimental approaches to perceptual dysfunction in schizophrenia]

METHOD

Starting from the studies of Conrad on early schizophrenia, we quantified the gestaltic alteration that he has described using a visual-motor gestaltic test (Bender test) in acute and chronic schizophrenic patients. We observed that rotations and distortions were significantly higher in chronic patients, and perseverations in acute patients. Global scores and time employed showed significant differences in both groups when compared with controls. Time is classically considered a compensation in the failure. We observed that the Bender gestaltic test allows quantification of perceptual alterations due to the loss of the objective structure of the perception in schizophrenic patients. Aiming to reproduce these findings in an animal model, we proposed a study of pharmacological modification of nucleus accumbens septi (Acc) neurotransmission, traditionally linked with physiopathology of schizophrenia. In this way, we developed a discrimination shape model in a skinner box in trained pigeons, bilaterally implanted in Acc by stereotaxic surgery.

CONCLUSIONS

The antagonists of N-methyl-D-aspartic acid (NMDA) glutamatergic receptor induced a significant decrease in performance in the discrimination task, and a significant increase in correcting trials. The last parameter was considered a perseveration, manifestation of a behavioral inflexibility in relationship with environmental changes. The glutamatergic blockade of Acc in rats using a passive avoidance task induced a disturbance in acquisition, and the same procedure in the plus maze test led to a significant decrease in anxiety levels, suggesting additional homologies with schizophrenic psychoses.

Behavioural consequences of nucleus accumbens dopaminergic stimulation and glutamatergic blocking in pigeons

Upon systemic administration of apomorphine, a potent dopamine agonist, pigeons show a bout of pecking behaviour. When the drug is repeatedly administered a sensitization takes place that is associated with pronounced discrimination learning. Here we show that intra-cerebral injections of apomorphine in the periphery of the nucleus accumbens of pigeons also elicit pecking. We additionally show that injections of 5-amino-phosphonohepatnoic acid, a NMDA-glutamate receptor blocker, into the Acc impairs the performance of a learned visual discrimination incorporating pecking as a choice response. We conclude that, as it is the case in mammals, the control mechanisms of learned sensory-motor behaviour in birds involves dopaminergic and glutamatergic synaptic transmission within the nucleus accumbens area.

Effects of selective NMDA and non-NMDA blockade in the nucleus accumbens on the plus-maze test

Effect of blocking N-methyl-D-aspartic acid (NMDA) and non-NMDA-glutamatergic receptors on performance in the plus-maze was studied in male rats bilaterally cannulated into the nucleus accumbens (Acc). Rats were divided into seven groups that received either 1 microl injections of saline, (+/-)2-amino-7-phosphonoheptanoic acid (AP-7, 0.2, 0.5, or 1 microg) or 2,3 dioxo-6-nitro-1,2,3,4,tetrahydrobenzo-(f)quinoxaline-7-sulphonamide disodium (NBQX, 0.2, 0.5, or 1 microg) 15 min before testing. Time spent in open arm, time per entry, end arrivals, open, closed, and total arm entries, relationship between open-, closed-, and total arm entries, rearing, face-, head-, and body grooming, and number of fecal boli were recorded. Time spent in the open arm increased under AP-7 (0.5 and 1 microg; P<.01) and NBQX (1 microg; P<.05) treatment, whereas time per entry was increased only with AP-7 (1 microg; P<.05). Open arm entries were increased by the intermediate doses of AP-7 (0.5 microg; P<.01) and NBQX (0.5 microg; P<.05); end arrivals were increased by the intermediate dose of AP-7 (0.5 microg/1 microl, P<.05). The frequency of rearing, grooming, and closed arm entries was not affected by the treatment. We conclude that NMDA and non-NMDA-glutamatergic blockade in the Acc lead to a behavioral disinhibition of cortical influences with the median doses, but that at higher doses the blockers have an anxiolytic-like effect.

AP-7 into the nucleus accumbens disrupts acquisition but does not affect consolidation in a passive avoidance task

The effect of the blockade of N-methyl-D-aspartic acid (NMDA)-type glutamatergic receptors in the nucleus accumbens septi (Acc) during different phases of a passive avoidance task (step-through paradigm, two chambers) of learning was studied in male rats which had been bilaterally cannulated into the Acc. Animals were trained with a punishment procedure (3 s shock of 1 mA) to avoid one of the chambers. The rats received either saline or (+/-)2-amino-7-phosphonoheptanoic acid (AP-7) solution (1 microg/1 microl) 10 min before training (pretraining schedule) or immediately after the shock (posttraining schedule). In the test phase, the animals were placed back into the white chamber after 1 and 8 days later. In this moment, rats stayed there for 1 min, after which the time elapsed between the removal of the door to the introduction into the dark chamber of the head (Latency 1) and body (Latency 2) and fecal boli expelled were recorded. In the pretraining injection schedule, the drug treatment significantly reduced Latency 2 (P<.05) and fecal boli (P<0.01) on Day 1, and all parameters on Day 8 (P<.05). The posttraining injection schedule did not modify behavior. We conclude that a preshock NMDA-glutamatergic blockade of the Acc leads to cognitive disturbances during acquisition and a decrease in anxiety levels, but that the consolidation of a learned task is not affected by postshock administration.

The anxiolytic effect of allopregnanolone is associated with gonadal hormonal status in female rats

The behavioural display in the plus-maze, an established experimental model of anxiety, was studied in rats injected into the lateral brain ventricle (i.c.v.) with the neurosteroid 3 alpha-hydroxy-5 alpha-pregnan-20-one (allopregnanolone). Female rats under different gonadal hormonal status were chosen. Allopregnanolone enhanced exploration of the open arms in both estrous rats and ovariectomized estrogen and progesterone primed rats. No effect was observed in diestrous 1 and ovariectomized not-primed rats. In all cases, the plus-maze locomotor-exploratory behaviour was not affected by allopregnanolone. The GABA(A) receptor antagonist, bicuculline (9.8 microM i.c.v.) reversed the allopregnanolone action in the ovariectomized primed rats. When bicuculline was injected i.c.v. in conjunction with allopregnanolone, the anxiogenic effect of bicuculline was reversed by the highest dose (25 microM) of allopregnanolone only. These results suggest that allopregnanolone exerts an anxiolytic action interacting with the GABA(A) receptor in an estrogen-dependent manner.

Visual discrimination in pigeons impaired by glutamatergic blockade of nucleus accumbens

The nucleus accumbens septi (Acc) is thought to be involved in the control of cognitive processes and to be implicated in the pathophysiology of schizophrenia. Because perceptual-cognitive distortions are a core symptom in schizophrenia, any evidence that the Acc intervenes in a sensory recognition task in an animal species would be of interest. Pigeons were instrumentally trained to discriminate visual shapes. The acute effects of drug microinjections into the Acc on the discrimination of the training shapes, on the correction responding after errors, and on the generalisation to different shapes were examined. The effects of conduction blockade with lidocaine, glutamatergic blockade with 7-aminophosphonoheptanoic acid, and dopaminergic stimulation with apomorphine on behavioural performance were tested. No effects were observed with lidocaine and apomorphine. A significant and reversible performance disruption to near chance levels was obtained after aminophosphonoheptanoic acid injections into the Acc. It appears that a glutamatergic blockade of the Acc interferes with the visual discrimination processes of pigeons.

Thyrotropin releasing hormone injected into the nucleus accumbens septi selectively increases face grooming in rats

The effect of unilateral injection of peptides into the nucleus accumbens septi (NAS) on subcategories of grooming behavior was studied in male rats. The peptides used were: thyrotropin releasing hormone (TRH), luteinizing hormone releasing hormone (LHRH) and corticotropin releasing hormone (CRH). Male rats (Holtzman strain, 240-270 g body weight) injected with progressive doses of TRH (100, 200 and 400 ng) at 5-day intervals were compared with the control state (injection of artificial cerebrospinal fluid, CSF). A selective increase in face grooming was observed with the 100 ng (49.78 +/- 6.11, N = 18) and 200 ng (50.29 +/- 7.72, N = 17) doses of TRH (P < 0.05 vs CSF injection, 26.94 +/- 3.64, N = 18). Face grooming increased further with the 400 ng dose (55.19 +/- 8.26, N = 16, P < 0.01), but a dose-response curve could not be obtained at the dose range used. Flank scratching, head, body and genital grooming were not altered by the TRH injection, but the rearing behavior was inhibited (10.33 +/- 1.56; N = 18; 10.76 +/- 1.77, N = 17; 12 +/- 2.06, N = 16) (P < 0.05 for all doses vs controls, 20.61 +/- 2.81, N = 18). The rats that received LHRH (75 ng, N = 16) and CRH (100 ng, N = 14) did not show behavioral changes when compared with their control states. The results show that injection of TRH into the NAS, but not the injection of LHRH or CRH, selectively increases face grooming without affecting other subcategories of grooming at the doses used, and appears to link this peptide with the neural substrate of stereotyped behavior.

Distinct grooming patterns induced by intracerebroventricular injection of CRH, TRH and LHRH in male rats

This paper reports the effects on grooming, related behaviors and levels of anxiety induced by the hypophysiotropic peptides corticotropin-releasing hormone (CRH, 1 microgram, 0.2 nmol, icv), thyrotropin-releasing hormone (TRH, 100 micrograms, 275 nmol, icv) and luteinizing hormone-releasing hormone (LHRH, 1.5 micrograms, 1.3 nmol, icv) administered into the lateral ventricle of the brain (icv) of adult male rats of a Holtzman-derived colony (N = 15, each group). CRH induced an increase in total grooming scores, whereas LHRH, TRH and vehicle had no effect. CRH strongly increased face and head grooming and induced head shakes. The time spent in rearing and gnawing was significantly decreased. In the plus-maze, CRH reduced the time of exploration in the open arm. TRH increased face grooming and induced body shakes. LHRH had no effect on grooming or rearing behavior. No body or head shakes were observed after LHRH administration. Scoring of individual grooming elements demonstrated differences in action of the three peptides. Although both CRH and TRH increased face grooming, only CRH induced head grooming. Furthermore, CRH induced predominantly head shakes while TRH increased body shake activity. In contrast, CRH was anxiogenic and TRH appeared to induce stereotyped behavior. From the characterization of grooming elements and related responses, we conclude that each hypophysiotropic peptide induces a specific behavioral pattern.

Effects of anxiety and memory of systemic and intra-amygdala injection of 5-HT3 receptor antagonist BRL 46470A

This study deals with the effects of the 5-HT3 receptor antagonist, BRL 46470A, on memory and anxiety, using the elevated T-maze. This method is useful for investigating the effects of anxiolytic drugs on memory, and the relationships between neural subsystems involved in emotionally related behaviors and in processes underlying learning. After the drug was either injected peripherally or microinjected into the amygdala, the animals were tested on the elevated T-maze (30 or 15 min later, respectively). Two kinds of aversively motivated behaviors, inhibitory avoidance and one-way escape, were recorded. These behaviors may reflect different types of fear/anxiety, namely, anticipatory anxiety and innate fear. Three days later, memory for these tasks was assessed by reexposing the subjects to the maze. The compound had an anxiolytic effect on the inhibitory avoidance response when given systemically, but an anxiogenic effect when injected into the amygdala. It had an anxiolytic action on the escape response when given either systemically or into the amygdala. The compound had no adverse effects on memory for either task. These results suggest that this new 5-HT3 antagonist may be useful in the treatment of certain types of anxiety disorders, especially those related to unconditioned fear, e.g. phobic or panic disorders, with the likelihood of having no side effects on memory processes. The contrasting results obtained with different measures of anxiety may also account for the inconsistencies found in the experimental literature dealing with compounds of this nature.

Interaction between glutamate and luteinizing hormone-releasing hormone (LHRH) in lordosis behavior and luteinizing hormone release (LH): further studies on NMDA receptor mediation

The present studies examine the effects of the glutamate agonist N-Methyl-D-Aspartic acid on lordosis responsiveness and LH release in estrogen-primed, ovariectomized rats. Groups of rats previously cannulated in the 3rd ventricle of the brain (IVT) were challenged with saline, NMDA and LHRH. A clear increase in lordosis-to-mount quotients (LQ) after IVT administration of 0.5, 0.75 and 1 microgram NMDA was found. LHRH (150 ng IVT) also enhanced LQ. High plasma LH levels were present in both cases. Intraventricular administration of the selective LHRH antagonist [D-p-Glu1, D-Phe2, D-Trp3,6]-LHRH (100 ng) was unable to prevent NMDA action on lordosis behavior. In contrast, it blunted LHRH enhancement of LQ. LH release evoked by either NMDA and LHRH was blocked by the LHRH antagonist. Present results support our previous view suggesting that glutamate, through NMDA receptors, participates in the regulation of lordosis behavior. Glutamate seems to exert its actions in the behavioral and endocrine patterns through different mechanisms; the first seems not to be mediated by LHRH, but the endocrine effect operates via LHRH release.

[Visual and motor functions in schizophrenic patients]

In the present work, visual and motor functions have been explored in 26 chronic schizophrenic patients, and 7 acute schizophrenic patients, compared with 26 normal controls, by means of the Bender-Gestalt Test. Parameters under consideration were: Form distortion, rotation, integration, perseveration, use of space, subtle motricity, score (global parameter), and time employed. As regards distortion and rotation there have been highly significant differences between chronic patients and control group. Among acute patients, it was observed that perseveration was also highly significant. Conversely, integration and use of space did not differ significantly among the three groups involved. The global score, resulting from all the above mentioned parameters showed important differences between both patient groups on the one hand, and control group on the other hand. Taking into account that patients were being administered neuroleptic drugs, it can safely be said, however, that the Bender-Gestalt Test allows to recognize alteration in perceptual closure consistent with a loss of the objective structure of perceived phenomena, in both chronic and acute patients.

Inhibition by N-methyl-D-aspartic acid (NMDA) receptor antagonist of lordosis behavior induced by estrogen followed by progesterone or luteinizing hormone-releasing hormone (LHRH) in the rat

The effects of glutamate receptor antagonists on sexual receptivity induced by progesterone and LHRH were examined in ovariectomized, estradiol-primed rats (OVX-EB). Enhancement of lordosis/mounts quotient (L/M) by progesterone (0.5 mg) or LH-RH (150 ng; third ventricle, IVT) in OVX-EB rats was significantly decreased by IVT injection of (+) 2-amino-7-phosphonoheptanoic acid a competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist. On the contrary, there were no changes in L/M quotient after IVT injection of 6,7-dinitroquinoxaline-2,3,dione at two dose levels, a Non-NMDA receptor antagonist. The NMDA antagonist did not modify lordosis behavior in OVX-EB rats. The results indicate that the NMDA type of glutamate receptors appears to mediate progesterone and LHRH facilitatory actions and suggest that glutamatergic synapses may be involved in lordosis-facilitating neural mechanisms.

Is inhibition by diazepam and beta-carbolines of estrogen-induced luteinizing hormone secretion related to sedative effects?

The effects of diazepam (DZ) and the beta-carbolines ZK-91296 and ZK-93423 on luteinizing hormone (LH) release evoked by beta-estradiol were studied in estradiol-primed ovariectomized rats. Acute treatment with 2.5, 5 and 10 mg/kg DZ and ZK-91296 significantly blunted the LH response. ZK-93423 (1, 5 and 10 mg/kg) produced a similar effect. The inverse agonist DMCM (2 mg/kg) was unable to modify plasma LH levels in estrogen-primed, ovariectomized rats. Sedative effects were observed with doses of DZ (1 mg/kg) ineffective to blunt the LH response. In contrast, ZK-91296 (5 mg/kg) produced inhibition of LH surges in nonsedative doses. These results indicate that diazepam and beta-carboline agonists prevent the LH surge evoked by estrogen. They suggest, in addition, that the actions on LH release and their sedative effects are not directly related.

Luteinizing hormone releasing hormone (LHRH) in the periaqueductal gray substance increases some subcategories of grooming behavior in male rats

Locomotion, holeboard exploration and grooming behavior were measured in male rats after injection of LHRH or cerebrospinal fluid (CSF) into the mesencephalic periaqueductal gray substance (PGS). LHRH injection at doses of 75 ng did not alter locomotion and rearing but decreased significantly the scores of head dipping and defecation. Several subcategories of grooming responses were evaluated in a home cage-like environment. Head, body and genital grooming increased significantly after injection of 75 ng LHRH. The frequency of gnawing and head shakes increased as well. Lower doses (50 ng) also raised the scores of head and body grooming and produced a tendency for genital grooming increase. Higher doses (100 ng) did not affect genital grooming responses and produced drowsiness in most of animals. These results demonstrate that some motor activities are selectively modified by the localized administration of LHRH in the PGS.