The Importance of Both Individual Differences and Dyadic Processes in Children's Emotion Expression

Although children display strong individual differences in emotion expression, they also engage in emotional synchrony or reciprocity with interaction partners. To understand this paradox between trait-like and dyadic influences, the goal of the current study was to investigate children's emotion expression using a Social Relations Model (SRM) approach. Playgroups consisting typically of four same-sex unfamiliar nine-year-old children (N = 202) interacted in a round-robin format (6 dyads per group). Each dyad completed two 5-minute tasks, a challenging frustration task and a cooperative planning task. Observers coded children's emotions during the tasks (happy, sad, angry, anxious, neutral) on a second-by-second basis. SRM analyses provided substantial evidence of both the trait-like nature of children's emotion expression (through significant effects for actor variance, multivariate actor-actor correlations, and multivariate intrapersonal correlations) and the dyadic nature of their emotion expression (through significant effects for partner variance, relationship variance, dyadic reciprocity correlations, and multivariate interpersonal correlations).

Spontaneous intracranial hypotension and epidural blood patch: a report involving seven cases

Spontaneous intracranial hypotension is a rare condition caused by spontaneous cerebrospinal fluid leak. It is characterised by orthostatic headache, diffuse pachymeningeal enhancement on brain imaging and low cerebrospinal fluid pressure. Seven patients with spontaneous intracranial hypotension were treated conservatively: of these, four responded to drug treatment and three underwent a lumbar autologous epidural blood patch (EBP). A complete response was obtained in two patients after a single EBP; one patient underwent a second EBP and then became asymptomatic. Clinical improvement coincided with a dramatic reduction of pachymeningeal enhancement. The aetiology and brain imaging findings, and the technique and effectiveness of EBP are discussed.

[Different use/abuse patterns (overweight/obesity, alcohol, smoking, drugs, cannabis, opiates, cocaine) according to job category. Results of a survey on 4024 young workers from Abruzzo, Italy: the Valentino Study]

Using a multidisciplinary questionnaire containing items from previously validated instruments (i.e. CAGE), during the year 2007 a survey (Valentino Project) was carried out on 4024 young workers (18-35 y) from Abruzzo, Italy to investigate the prevalence of use/abuse of alcohol, food, smoking, and drugs in different types of job categories, and to evaluate the potential association between occupational class and type of use/abuse. With the exception of cannabis use/abuse (13.5%), the prevalence of incorrect behaviours was higher than the young-adult general population (workers and non-workers) from Central-South Italy: overweight/obesity = 30.8%; current smoking = 45.7%; alcohol addiction = 17.3%; use/abuse of psychotropic legal drugs = 4.7%; cocaine = 4.5%; opiates = 1.0%; > 1 illegal drug (multiple abuse) = 3.9%. This negative scenario is accentuated by a probable > or = 25% underestimation of illegal drug use/abuse, and because drug use/abuse is inversely associated with age. Using logistic regression analyses (controlling for age, gender marital status, education, job-strain, self-reported health, and all other types of use/abuse), a significant independent association was found for the first time between specific types of use/abuse and some job categories (i.e. cocaine for traders/consultants; legal psychoactive drugs and cannabis for unqualified professions such as itinerants or precarious workers; smoking for Call-Center operators; overweight/obesity for farmers/artisans). These findings should be used to maximize the efficacy of substance use/abuse preventive strategies, which could be more precisely targeted to different professions, and raise the need to control for job category in future multivariate analyses investigating substance use/abuse predictors.

Validation of AIDA Cefalee, a computer-assisted diagnosis database for the management of headache patients

AIDA Cefalee is a database for the management of headache patients developed on behalf of the Italian Neurological Association for Headache Research (ANIRCEF). The system integrates a diagnostic expert system able to suggest the correct ICHD-II diagnosis once all clinical characteristics of a patient's headache have been collected. The software has undergone a multicentre validation study to assess: its diagnostic accuracy; the impact of using the software on visit duration; the userfriendliness degree of the software interface; and patients' acceptability of computer-assisted interview. Five Italian headache centres participated in the study. The results of this study validate AIDA Cefalee as a reliable diagnostic tool for primary headaches that can improve diagnostic accuracy with respect to the standard clinical method without increasing the time length of visits even when used by operators with basic computer experience.

Multiple sclerosis and headache co-morbidity. A case-control study

The prevalence of primary headache (PH) in a multiple sclerosis (MS) sample vs. control healthy subjects was investigated at a neurological clinic in 2004-2005: 122 of 238 (51%) MS patients and 57 of 238 (23%) controls proved to be affected by headache. The groups did not differ for the rates of PH types. Headache types of MS patients were comparable to those of PH patients that were observed at the same institute in a case-control comparison. First symptoms of headache preceded those of MS in two thirds of cases. Headache features did not significantly change after MS onset. Comorbidity of MS and PH could be explained by some common clinical and biological traits.

Migraine and epilepsy: clinical and pathophysiological relations

Migraine and epilepsy are both chronic disorders characterised by recurrent neurological attacks, with a partial clinical and therapeutic overlap and frequently occurring together. Although still incompletely clarified, the possible existence of a link between migraine and epilepsy has long been debated. In this paper the epidemiologic evidence of migraine and epilepsy comorbidity, the possible occurrence of both disturbances in close temporal association, possible shared physiopathologic mechanisms and the rationale for antiepileptic drug use in migraine prophylaxis will be discussed.

Hypnic headache: an update

Hypnic headache (HH) is a rare sleep-associated primary headache disorder, usually affecting aged people, first described by Raskin in 1988. The headache attacks, single or multiple in one night, occur exclusively during sleep and tend to present at a consistent time each night, sometimes during a dream. Compared to the original description, newly reported cases have expanded the clinical spectrum of the disorder to include unilateral forms (about 40%, half of which are side-locked), forms with a longer duration (up to 3 h) and cases with onset in juvenile/adult age. The male predominance found in Raskin's series has not been confirmed by subsequent observations. To date the reported F/M ratio is 1.7/1. Pain is of severe intensity in less then one-third of cases and mild-moderate in about two-thirds. The location of pain is fronto-temporal in over 40% of cases; headache is throbbing in 38% of cases, dull in 57% and stabbing in less than 5%. Nausea is reported in 19% of cases; photophobia, phonophobia or both are present in 6.8%. Mild autonomic signs (lacrimation, nasal congestion, ptosis) may rarely be present. In 2004, HH was included in Group 4 of the International Classification of Headache Disorders-II (Other primary headaches). Sufficient evidence, mainly from polysomnographic studies, indicates that HH is a primary rapid eye movement (REM) sleep-related headache disorder of chronobiological origin. Lithium, melatonin, indomethacin and caffeine at bedtime are among the most effective therapeutic options. The pathophysiology of HH is still unclear. Available data allow speculation that, in predisposed subjects, an age-related impairment of suprachiasmatic nucleus could cyclically activate a disnociceptive mechanism leading to both a sudden awakening and headache. The mechanism may be precipitated by neurophysiologic events such as the strong reduction of firing occurring in the dorsal raphe nucleus during a REM sleep phase.

A clinical comparison of trigeminal neuralgic pain in patients with and without underlying multiple sclerosis

Despite clinical similitude, there is a tendency to consider trigeminal pain in multiple sclerosis (MS) as a distinct condition. To evaluate clinical differences in trigeminal pain presentation in patients with and without underlying MS, we compared clinical characteristics of facial pain found in 15 consecutive MS patients with those reported by 13 consecutive subjects diagnosed with classical trigeminal neuralgia. The only significant difference between MS and non-MS neuralgic patients was the age of onset of pain (43.4+/-10.5 in MS vs. 59.6+/-11.50 in non-MS patients, p=0.000629, unpaired Student's t-test). No differences were observed for side, duration and quality of pain, trigeminal branches involved, presence of trigger areas or factors, pain refractive period, remitting-relapsing or chronic course. There was only a trend without statistical significance in interval pain and trigeminal hypoesthesia, more frequent in MS population. Only one patient in the MS group presented with long-lasting episodes (45-60 min) of atypical odontalgia. Our findings support the view of a common pathogenetic mechanism underlying TN in the two groups, possibly related to demyelination of the trigeminal entry root in the pons. Typical TN in MS patients should be considered as "symptomatic trigeminal neuralgia".

Sudden re-opening of collapsed transverse sinuses and longstanding clinical remission after a single lumbar puncture in a case of idiopathic intracranial hypertension. Pathogenetic implications

The aetiopathogenetic role of sinus venous obstructions carried by most idiopathic intracranial hypertension (IIH) patients is controversial. We report the case of a young woman diagnosed with IIH with papilloedema and narrowing of transverse sinuses, in which lowering of intracranial pressure by a single 20 ml cerebrospinal fluid (CSF) resulted in a strong dimensional increase of the transverse sinuses. Changes were followed by clinical remission and normalisation of optical nerve calibre, maintained after a 2-month follow-up. Our findings indicate that, although secondary to CSF hypertension, venous sinuses compression may have an important role in hypertensive status maintenance. Pathogenetic implications of venous sinus compression by hypertensive CSF in IIH are discussed.

Kinematic strategies for lowering of upper limbs during suggestions of heaviness: a real-simulator design

The aim of the experiment was to study possible differences between the kinematic strategies for the "involuntary" arm lowering of hypnotized highly susceptible subjects (H-Highs) and for the voluntary movement of non-hypnotizable simulators (Sims) during suggestions of arm heaviness (Part I). In addition, a comparison between awake susceptible subjects (W-Highs) and H-Highs was carried out to clarify the specific role of the hypnotic state and hypnotizability (Part II). Subjects' absorption and attentional/imagery capabilities were evaluated through neuropsychological tests. Their arm movements were monitored three-dimensionally at hand, wrist and elbow level through a Polhemus Fastrack system. A final interview collected self-reports concerning the perception of movement involuntariness. Neuropsychological tests showed better "absorption" and imagery capabilities in Highs. In the interview, H-Highs perceived a higher involvement in the task and greater involuntariness and difficulties in contrasting the arm lowering than the Sims. Kinematic analysis showed significant differences between H-Highs and Sims for arm displacements along the vertical axis and on the horizontal plane. In fact, the former lowered the left arm earlier and to a greater degree than the right arm; on the horizontal plane, a forearm flexion was observed for H-Highs on the right side. On comparing W-Highs and H-Highs, hypnosis appeared to magnify the waking motor strategies, but also to induce specific changes, mainly concerning the horizontal plane. These results cannot be interpreted on the basis of "role playing" and socio-cognitive factors. They are believed to be due to a balance between the effectiveness of the frontal executive control towards the selection of behaviors and movement automaticity, which is in line with the neo-dissociation theory of hypnosis.

Towards the computerisation of ANIRCEF Headache Centres. Presentation of AIDA CEFALEE, a computer assisted diagnosis database for the management of headache patients

Because of the lack of biochemical or neuroradiological markers, the diagnostic assessment of primary headaches rests on a clinical history collected by an experienced physician; the articulated criteria of the International Headache Society (IHS) represent the only available tool to test objectively the diagnostic hypothesis rising from clinical interview. However, the complexity reached by IHS criteria still represents its major limit to extensive application, at least in common clinical settings. The use of modern information technology (IT), which is specifically designed to manage complex problems with a large number of variables, seems to be the best choice to counteract the complexity of IHS classification. In this paper AIDA CEFALEE, a user-friendly client-server database for the management of headache patients, is presented. The system integrates a computer assisted diagnosis module, which may help to extend the correct use of IHS diagnostic criteria to any clinical setting. The interoperability of the system may represent the possible infrastructure of a National Network of ANIRCEF Headache Centres.

HELLP syndrome with reversible posterior leukoencephalopathy

We report the case of a 30-year-old primipara who developed a triplet pregnancy after having received artificial insemination. At the end of the eighth month of pregnancy she had a generalized tonic-clonic seizure and at the same time blood chemistry was indicative of HELLP syndrome. Brain MRI and EEG were altered immediately after the episode but returned to normal during a 6-month follow-up period.

The thymus and myasthenia gravis: immunological and neurophysiological aspects

Myasthenia gravis (MG) is an autoimmune disorder, in which end-plate membrane damage is induced by antibodies directed toward various epitopes of the main immunogenic region of the nicotinic acetylcholine receptor (AChR). This article reviews the mechanisms responsible for the development of MG. Recent investigations into the roles of the thymus, antibodies against AChR, cytokines, and neuromuscular transmission have given new insight into the pathogenesis of MG. These new advances have led to a better understanding of the immune mechanisms in MG and have opened new therapeutic horizons.

Long-term outcome of migraine therapy: predictive value of the frontotemporal nitroglycerin test

We evaluated whether type of response to the migraine-induction test with a nitroglycerin ointment applied to the frontotemporal head region could predict the efficacy of antimigraine therapy. Forty-two patients with migraine without aura underwent the test before and 2 months after antimigraine therapy. Two and 4 months after treatment withdrawal, most subjects with a negative response to the post-treatment test maintained treatment benefit, whereas benefit was lost in patients with an early onset migraine response.

The frontotemporal region plays a role in the genesis of migraine without aura

We have compared the migraine-inducing effect of nitroglycerin ointment applied to the frontotemporal region of the head, which is innervated by the ophthalmic and maxillary divisions of the trigeminal nerve, with that of nitroglycerin applied to the chin (innervated by the mandibular division), the posterolateral region of the neck (innervated by the second and third cervical roots), the lateral surface of the proximal third of the forearm (innervated by the sixth cervical root), and the medial surface of the upper-arm region (second dorsal root). One hundred patients suffering from migraine without aura were randomly divided into five equal groups. Each group received an application of 5 mg nitroglycerin in 2% ointment on a preselected body area for 2 hours. Frontotemporal nitroglycerin induced a significantly greater number of early onset migraine attacks with respect to the arm and forearm regions. In all cases, nitroglycerin applied to the frontotemporal region resulted in subsequent migraine, whereas there was a significant number of negative trials with nitroglycerin applied to the neck, arm, and forearm vs the frontotemporal area. It, therefore, appears that the trigeminal nerve endings in the affected frontotemporal region are particularly sensitive to the migraine-inducing effect of the nitrate. This suggests a peripheral neurogenic hypothesis of migraine genesis.

The antimigraine effect of ergotamine: a role for alpha-adrenergic blockade?

The hypothesis that alpha-adrenergic receptor blockade accounts for the ability of ergotamine to stop migraine attacks was tested, in migraine patients, in an experimental migraine model based on nitroderivative- induced attacks. In a preliminary single blind, placebo controlled study, thymoxamine, a prevalently post-synaptic alpha adrenergic receptor antagonist, was able to abort migraine attack in 9 out of 10 patients, as opposed to 2 out of 10 by placebo (p < 0.005 Fisher's exact test). In a subsequent randomized, crossover, placebo controlled double blind study, the ability of a selective alpha-1 adrenergic receptor agonist, methoxamine, to block ergotamine antimigraine effect was studied. In 26 patients migraine was induced in two separate tests and then ergotamine was administered once after methoxamine pretreatment and once after placebo; methoxamine was significantly more effective than placebo in blocking antimigraine effect of ergotamine (p = 0.0055 Fisher's exact test). These results support the hypothesis that ergotamine alpha-1 adrenolytic properties may account for its antimigraine effect suggesting that this action takes place outside the blood-brain barrier, since methoxamine can cross it very poorly. Ergotamine target structure could be the trigeminal innervation of the extracranial and/or dural vessels.

Thymectomy for myasthenia gravis: predictive factors and long term evolution. A retrospective study on 46 patients

Forty-six patients with myasthenia gravis (MG) underwent transternal thymectomy between 1975 and 1991 and were observed over a long term follow up period (mean 6 years). Surgery was well tolerated and was followed in 32.6% of patients by remission of symptomatology. The severity of symptoms according to the Osserman scale was significantly reduced: slight forms of myasthenia increased soon after thymectomy more frequently than moderate and severe forms. Response to thymectomy at 3 months, according to the Hankins scale, was found to be positive (remission or amelioration of symptoms) in 31/41 patients, and worse in patients with thymoma. Probability of clinical remission and death were both significantly correlated with clinical response at three months after thymectomy. No other preoperatory clinical factor (onset age, sex, initial severity of MG, interval from symptom onset to thymectomy) was found to predict the response to treatment. Preoperatory mediastinic CT had a good reliability (> 85%) in diagnosing thymona, but was rarely able to distinguish between thymic hyperplasia and atrophy.

Allergy to different fish species in cod-allergic children: in vivo and in vitro studies

The presence of a positive clinical history and skin test (ST) results for 17 fish species (anchovy, bass, carp, dogfish, eel, gilthead, mackerel, mullet, perch, red mullet, salmon, sardine, sole, tench, toothed gilthead, trout, and tuna) were investigated in 20 children with cod-positive clinical history, ST, and RAST, and in 40 children positive to one or more foods different from cod (cow's milk, chicken egg white, peanut, and tomato). In cod-positive children, positive clinical history (60%) and ST (85%) to fish species were more frequent than in cod-negative children (7.5% and 10% respectively). In cod-positive children, a high frequency of positive STs to eel (85%) and to bass, dentex, sole, and tuna (55%) was observed. Positivity to dogfish (10%) was the least frequent. RAST-inhibition experiments suggested the presence of cross-reacting antigen(s) in cod, bass, dentex, eel, sole, and tuna. Results of this study demonstrate that cod allergy might be, on the whole, a reliable index of fish allergy, but cod-positive children may perhaps tolerate some other species, which will have to be tested for possible inclusion in their diet.

[Possible mechanisms of the action of drugs for hemicrania]

Different classes of drugs are used in the pharmacological treatment of headache, both during migraine crisis and migraine prophylaxis. How these drugs exert their therapeutical effect in migraine is not clearly understood. Hypothetical mechanisms of action are discussed by the Authors in regard to the different pathogenetical events relevant to migraine. It is proposed that different pathological events can be modified by one drug and, conversely, one mechanism of action may be common to different drugs.

Source of pain and primitive dysfunction in migraine: an identical site?

Twenty common migraine patients received a one sided frontotemporal application of nitroglycerin (10 patients) or placebo ointment (10 patients) in a double blind study. Early onset migraine attacks were induced by nitroglycerin in seven out of 10 patients versus no patient in the placebo group. Subsequently 20 migraine patients, who developed an early onset attack with frontotemporal nitroglycerin, received the drug in a second induction test at other body areas. No early onset migraine was observed. Thus the migraine-inducing effect of nitroglycerin seems to depend on direct stimulation of the habitual site of pain, suggesting that the frontotemporal region is of crucial importance in the development of a migraine crisis. This is not consistent with a CNS origin of migraine attack.

Steroid-induced disappearance of primary central nervous system lymphoma. Clinical, neuroradiological and pathological findings

A 73-year-old man presented a progressive neurologic syndrome with impairment of multiple cranial nerves, ataxia and limb weakness. Neuroradiological evaluation showed multiple supra and infratentorial lesions, which completely disappeared after steroid treatment on two occasions. These neuroradiological modifications were closely correlated with clinical picture and CSF findings. Post-mortem examination showed multifocal primary CNS immunoblastic large cell lymphoma. Immunohistochemistry showed that the tumor was of B-cell origin.

[Importance of a particular formula of soybean milk without S2 globulin, in the treatment of allergy to cow's milk proteins]

Replacing cow's milk with a soybean milk is one of the first measures which are commonly taken with babies suffering from cow's milk protein allergy. Unfortunately soybean can induce sensitization, too, with a variable percentage (ranging from 12 to 80%) according to the different Authors, due to the presence of allergenic proteins, among which the most important one seems to be S2 globulin. An excellent tolerability has been reported in a study carried out with 20 babies suffering from cow's milk protein allergy besides a good palatability of the product with a solution of symptoms in 87.3% of the cases. Only in 16.7% of the treated babies intolerance has been reported and therefore we can conclude that soybean milk has proved to be an excellent substitute of cow's milk in babies suffering from cow's milk protein allergy.

[Radiologic examination of the paranasal sinuses in asthmatic children]

We examined the prevalence of abnormalities found by sinus X-Rays in 80 asthmatic children classified into three groups in relation to severity of their symptoms. All the children underwent skin tests and some of them methacholine challenge. 63.7% of asthmatics showed abnormalities in sinus X-Rays. No correlation was found between the severity of asthma, radiographic findings, and atopic status. Bronchial hyperreactivity studied using metacholine challenge according to the method of Chai was the same both in patients with asthma and sinusitis and in those with asthma only. In conclusion, abnormal sinus X-Rays do not seem to be an aggravating factor in asthmatic status.

Flunarizine in prophylaxis of childhood migraine. A double-blind, placebo-controlled, crossover study

An 8-month, double-blind, placebo-controlled, crossover trial of flunarizine in the prophylaxis of migraine has been performed in 70 children. After 4 weeks of medication-free base-line observation, 35 children (group A) received flunarizine (5 mg/day) and 35 (group B) received placebo over a 12-week period. After a 4-week washout they crossed treatments for another 12 weeks. Sixty-three patients completed the trial. In both groups flunarizine significantly reduced the frequency and average duration of headache attacks. In group A efficacy was maintained after placebo crossover for the last 4 months of the study. Five subjects in group B stopped placebo because of ineffectiveness; two children in group A discontinued flunarizine treatment, one because of excessive daytime sedation and the other because therapy was ineffective. The main side effects were daytime sedation and weight gain. It is concluded that flunarizine is an effective drug for the treatment of childhood migraine. In a study of this length no serious side effects were discovered.

[Epstein-Barr virus infection. Old and new immunological aspects]

EBV infection may have a wide range of clinical consequences: it is often asymptomatic; some cases-generally adolescents-develop the classic "infectious mononucleosis" syndrome; in rare cases the illness takes a severe, fatal course. EBV is also implicated in some geographic areas, in Burkitt' lymphoma and naso-pharyngeal carcinoma. Recent research has enrich our knowledge on the viral genome and the various viral antigen, but some problems are still unsolved. The "normal" immunological response to EBV infection is briefly summarized; then the abnormal immunological pattern is considered in relation to some conditions such as age, congenital and acquired immunodeficiencies and unusual clinical syndromes. Recently a group of not well defined, persistent illnesses (fever, fatigue, headache etc.) has been correlate to a "chronic" EBV infection. It becomes more and more evident that different clinical manifestations of EBV infection are always connected with a particular immunological response; between the "normal" cases and those with well defined immunodeficiency probably large group exists in which minor immunological abnormalities are responsible for a partial derepression of the virus.

Prophylaxis of migraine attacks with a calcium-channel blocker: flunarizine versus methysergide

In this study, flunarizine, a selective calcium-channel blocker, was employed in the prophylactic treatment of headache and was compared with methysergide in terms of efficacy. The trial was conducted with 104 patients (53 treated with flunarizine and 51 treated with methysergide) and lasted six months--one month of pretreatment and five months of therapy. Patients in both groups experienced a highly significant reduction in the number and duration of migraine attacks. Unlike those in the methysergide group, patients treated with flunarizine achieved a significant reduction in the intensity of attacks with very negligible side effects.

Flunarizine v. placebo in childhood migraine. A double-blind study

Successful migraine prophylaxis with flunarizine has been reported in adults by several authors. We used flunarizine in a double-blind, placebo controlled, randomized trial in childhood migraine. Twenty-four children with classical or common migraine were followed by a 12-week flunarizine treatment period. Each patient took 5 mg/day of the drug before going to sleep. Twenty-four children with similar clinical characteristics were assigned to placebo treatment. Efficacy of flunarizine versus placebo was assessed on the basis of the reduction of headache frequency and duration. A statistical comparison was performed between values reported in the treatment period and those in the three months before. Children treated with flunarizine experienced a statistically significant reduction in headache (66%) and duration (51%). These results were statistically superior to those observed in the placebo group. Sixteen patients on flunarizine therapy experienced an improvement of more than 50% of both parameters. We found flunarizine is an effective agent in children's migraine prophylaxis. Moreover it is suitable for the low incidence of mild side effects.

Efficacy of baclofen in trigeminal neuralgia and some other painful conditions. A clinical trial

Baclofen (beta-4-chlorophenyl-gamma-aminobutyric acid) shows analgesic properties in rats and resembles carbamazepine and phenytoin in its effects on the spinal trigeminal nucleus of cats. We have, therefore, conducted a clinical trial in 25 subjects, 16 suffering from trigeminal neuralgia, and 9 patients were affected by different painful conditions such as postherpetic neuralgia, tabes dorsalis, postarachnoid radiculitis. 5 of the former groups were refractory to or unable to tolerate carbamazepine. Baclofen has significantly exhibited analgesic efficacy: all groups, as a whole, were improved by 68.61%. These results substantiate that baclofen is useful in the treatment of trigeminal neuralgia and other painful conditions.

Evidence for a dose-dependent effect in the sex-specific plasma prolactin response to naloxone in humans

In attempt to ascertain if the sex specific plasma PRL response to naloxone, that we suggested in previous studies, was a dose dependent effect, 26 healthy volunteers were studied. They received naloxone 2 mg and 4.8 mg or a volume matched of saline i.v. as a bolus. Blood samples were collected and plasma PRL was measured by double antibody RIA. Naloxone, at dose of 2 mg, was able to decrease significantly plasma PRL levels in normally menstruating women (p less than 0.05 at 60 min.; p less than 0.01 at 120 min.), but not in post-menopausal ones and in men. In addition, the dose of 4.8 mg of the drug did not change plasma PRL in any group. These results suggest a dose-dependent effect in the sex specific PRL response to naloxone in humans.