Microinfusion of cocaine into the medial preoptic area or nucleus accumbens transiently impairs maternal behavior in the rat.

Cocaine was microinfused bilaterally (50 μg/0.5 μl/side) into the medial preoptic area (MPOA) or nucleus accumbens (NA), 2 regions within the rat brain neural circuit known to mediate maternal behavior (MB). Additionally, 2 sites not involved in this neural circuit, the dorsal striatum and dorsal medial hippocampus, were used as control sites. Microinfusion of cocaine into the MPOA or NA impaired MB, whereas infusion into the control sites did not. MB impairment was not temporally coincident with the increased locomotor activity, also documented after cocaine infusion into the MPOA or NA, arguing strongly that impaired MB is a direct, specific effect of cocaine in these areas, not a derivative of increased motor activity. This is the first demonstration that cocaine action on single central nervous system (CNS) sites can impair MB to the same extent as systemic injections. Thus, cocaine's simultaneous effect on multiple CNS sites is not required for MB impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cocaine impairs maternal nest building in pregnant rats

The present study investigated the onset of maternal nest building in pregnant Fischer rats following chronic repeated cocaine administration. Pregnant Fischer rats were injected with saline or cocaine, 15 mg/kg, three times daily at 1-h intervals for 10 days starting on gestation day 8. Cocaine-exposed females incorporated less material into their nests and built fewer fully completed circular nests than control animals. The overall quality of the nest in cocaine exposed dams was significantly lower than that of control animals. Furthermore, cocaine exposed dams gained less weight than control females. However, no difference in number of pups, weight, or length of pups was observed between groups. Thus, it seems that cocaine disrupts the interest and skill in nest building of pregnant rats.     

Cocaine alters behavior in the rat fetus.

Changes in motor behavior and sensory responsiveness were characterized in rat fetuses on Gestational Day 21 after acute administration of various doses of cocaine. An increase in fetal motor activity was evident in the 3 highest doses (5, 10, and 20 mg/kg). Cocaine-exposed Ss showed reduced facial wiping in behavioral bioassays of cutaneous sensitivity (10 and 20 mg/kg) and chemosensory responsiveness (20 mg/kg). Changes in other behavioral measures indicated that fetuses detected and responded to these stimuli, suggesting that reduced facial wiping was due to a disruption of sensorimotor integration or motor coordination. Study of the fetus in vivo can provide insights into the mechanisms of cocaine's deleterious effects on CNS and behavioral development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hysterectomy-induced maternal behavior pregnancy in the rat.

Performed hysterectomies between the 10th and 19th day of pregnancy, and tested females with pups for the onset of maternal behavior starting 0, 24, 48, or 72 hr after surgery. Ss were 394 Charles River female rats. Pups remained with females overnight, and testing was repeated daily with fresh pups until females exhibited maternal behavior. Latencies for the onset of maternal behavior were shorter after hysterectomy on the 10th and 16th days of pregnancy than in intact pregnant Ss at the same stages of pregnancy; latencies become shorter, the later the termination of pregnancy. When the ovaries were removed along with hysterectomy during pregnancy, short-latency maternal behavior no longer was exhibited. Pregnant Ss were tested during the last 40 hr of pregnancy: nest building began at 34 and retrieving at 28 hr prepartum. The effect of hysterectomy during pregnancy on ovarian secretion of estrogen and progesterone is reviewed, and it is concluded that the rise in estrogen secretion, which follows hysterectomy during pregnancy, is most likely the cause of the rapid onset of maternal behavior after hysterectomy. A similar proposal is made for the prepartum onset of maternal behavior in intact pregnant females. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cocaine treatment and prenatal environment interact to disrupt intergenerational maternal behavior in rats.

The link between impaired maternal behavior (MB) and cocaine treatment could result from drug-induced decreases in maternal reactivity to offspring, prenatal drug exposure (PDE) in offspring that could alter their ability to elicit MB, or the interaction of both, which could subsequently impair MB of the 1st-generation dams. Following chronic or intermittent cocaine or saline treatment during gestation, rat dams rearing natural or cross-fostered litters were compared along with untreated dams for MB. Untreated 1st-generation females with differentially treated rearing dams and PDE were tested for MB with their natural litters. The authors report disruptions in MB in dams and their 1st-generation offspring, attributable to main and interaction effects of maternal treatment, litter PDE, and rearing experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cocaine significantly impairs myocardial relaxation

OBJECTIVES: To determine the immediate effects of intravenous "recreational" doses of cocaine on myocardial ventricular relaxation and contraction and on coronary blood flow. To determine the cardiac effects of cocaine after the administration of propranolol, as propranolol has been used to limit the cardiovascular effects of cocaine. DESIGN: Prospective study. SUBJECTS: Twenty mongrel dogs. INTERVENTIONS: We continuously recorded central aortic pressure, left atrial and ventricular pressures, coronary artery blood flow, and electrocardiograms in each dog. We determined from the left ventricular pressure waveforms the maximum rate of pressure increase [(dP/dt)max] and the time constant of isovolumic ventricular relaxation as our indices of ventricular contraction and relaxation. MEASUREMENTS AND MAIN RESULTS: In our initial series of experiments, we obtained pressure, coronary artery blood flow, and electrocardiographic recordings in ten anesthetized dogs before and for 40 mins after the intravenous administration of cocaine, in doses of 2.5 and then 5 mg/kg. In our second series of experiments in ten additional dogs, we injected 0.5 mg/kg of propranolol intravenously 30 mins before the injection of cocaine (2.5 mg/kg), and obtained hemodynamic and electrocardiographic recordings before and for 40 mins after the injection of propranolol and cocaine. Cocaine, 2.5 mg/kg, abruptly increased the time constant of isovolumic ventricular relaxation from 22.9 +/- 1.2 to 29 +/- 2.2 msecs at 1 min (p < .05) and to 35.3 +/- 2 msec at 40 mins (p < .01) but did not significantly change the mean arterial pressure, left atrial pressure, heart rate, coronary blood flow, or the maximum rate of left ventricular pressure increase [(dP/dt)max]. Cocaine also progressively displaced the electrocardiographic ST segments by 3.2 +/- 0.6 mm (p < .01) over 40 mins. Cocaine, 5 mg/kg, rapidly increased the time constant of isovolumic ventricular relaxation from 28.5 +/- 2.5 to 41 +/- 3 msecs in 1 min (p < .05) and to 48.7 +/- 4 msecs at 40 mins (p < .01) and reduced (dP/dt)max from 2905 +/- 370 to 1422 +/- 121 mm Hg/sec at 1 min (p < .01); (dP/dt)max returned to 2351 +/- 415 mm Hg/sec during the next 39 mins. Cocaine did not significantly change either the mean arterial or left atrial pressures. However, this dose of cocaine did decrease, over 40 mins, the heart rate from 184 +/- 11 to 139 +/- 11 beats/min (p < .01) and reduced coronary blood flow by 20% (p < .01). Cocaine also displaced the electrocardiographic ST segments by 3.3 mm over 40 mins (p < .05). Cocaine and propranolol abruptly increased the time constant of isovolumic ventricular relaxation from 26.4 +/- 1.3 to 43.2 +/- 2.1 msecs (p < .01) at 1 min and to 46.8 +/- 1.5 msecs at 3 mins (p < .01). The time constant of isovolumic ventricular relaxation remained abnormally increased at 43.0 +/- 1.4 msecs at 40 mins. Cocaine and propranolol reduced (dP/dt)max from 2760 +/- 458 mm Hg/sec to a minimum value of 1400 +/- 119 mm Hg/sec at 2 mins (p < .01). However, (dP/dt)max then returned to 2201 +/- 359 mm Hg/sec during the next 38 mins. Cocaine and propranolol did not significantly change the mean arterial and left atrial pressures, or heart rate, but did reduce coronary blood flow, over 40 mins, by 25% (p < .001). Cocaine also maximally displaced the electrocardiographic ST segments by 1 +/- 0.2 mm (p < .01). CONCLUSIONS: Cocaine substantially impairs myocardial ventricular relaxation for periods of at least 40 mins. Propranolol significantly intensifies cocaine's depressant effect on ventricular relaxation.     

Medial preoptic area and maternal behavior in the female rat.

Reports results of 3 experiments with a total of 92 postpartum lactating female Wistar rats. Medial preoptic area lesions severely disrupted maternal behavior, whereas lesions of the stria terminalis and medial cortico-hypothalamic tract knife cuts were without effect. Parasagittal knife cuts that severed the mediolateral connections of the preoptic-anterior hypothalamic continuum also severely disrupted maternal behavior. The lesions and knife cuts which disrupted maternal behavior had no effect on female sexual behavior. It is concluded that the medial preoptic area and its lateral connections are essential for the normal display of maternal behavior in postpartum lactating female rats. Evidence also indicates that independent neural mechanisms for the control of maternal behavior and sexual behavior exist within the hypothalamus of female rats. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decline of maternal behavior in the virgin and lactating rat.

Gave to sensitized virgins and postpartum lactating mothers, both exhibiting maternal behavior, donor litters that increased in age by 1 day, for 28 days, starting at the onset of maternal behavior. Ss were 18 Charles River rats. Each day Ss were tested for maternal behavior with 4-8 day old pups. Maternal care (i.e., nursing-crouching, retrieving, nest building, and licking and maternal withdrawal, rejection, and prevention of nursing were recorded. After the 9th day, Ss were also tested with the progressively older pups 10-28 days of age with which they were living. Virgins and lactating mothers showed generally similar patterns of maternal care although some differences were found, and they declined in maternal behavior toward the older pups in a similar manner. Maternal behavior did not decline in tests with younger pups. Results are interpreted as supporting the hypothesis that the decline as well as the maintenance of maternal behavior postpartum is nonhormonally mediated. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Medial preoptic area and onset of maternal behavior in the rat.

Three experiments examined whether the medial preoptic area (MPOA) is involved in the onset of maternal behavior in the rat. Exp I, with 54 female Charles River CD rats, investigated whether estradiol benzoate (EB) acts on the MPOA to facilitate the onset of maternal behavior in 16-day pregnant, hysterectomized, and ovariectomized Ss. When given EB implants in the MPOA, these Ss had significantly shorter latencies for the onset of maternal behavior than those implanted with cholesterol in the MPOA or with EB in the ventromedial hypothalamus, in mammillary bodies, or under the skin. Exp II, with 62 Ss, showed that estrogen-induced prolactin release was not involved in this facilitation. Exp III, with 35 Ss, showed that MPOA lesions disrupted the onset of maternal behavior induced by pup stimulation in virgin females. (11/2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An NMDA antagonist impairs copulation and the experience-induced enhancement of male sexual behavior in the rat.

Sexual experience facilitates subsequent male sexual behavior; activation of the N-methyl-D-aspartate (NMDA) glutamate receptor may play a role in this experience-induced enhancement. In this article, the authors report that systemic injections of MK-801, an NMDA receptor antagonist, impaired male sexual behavior in sexually naive and sexually experienced male rats. Furthermore, saline-treated rats that received 7 daily exposures to an inaccessible estrous female instead of sexual experience displayed enhancement of copulation on the following day. Injections of MK-801 before each of these exposures inhibited the experience-induced enhancement on the drug-free test on Day 8. These data suggest that stimulation of NMDA receptors enhances sexual performance immediately and mediates the experience-induced enhancement of subsequent copulatory behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cocaine impairs follicular phase pulsatile gonadotropin secretion in rhesus monkeys

BACKGROUND: Ménière's disease is a medical condition that involves hearing loss, tinnitus and attacks of vertigo. The attacks can be severely disabling with nausea, dizziness, and aural sensations. METHOD: Three scales assessing the correlates of vertigo attacks in Ménière's disease were developed and completed by 514 subjects diagnosed with the disease. The three scales measured were somatic sensations (SOM), psychological state (PSYCHOL), and situational characteristics (SIT) associated with an attack. RESULTS: Psychometric properties of the three scales were investigated showing Cronbach's alphas of 0.76, 0.80, and 0.62 for the three scales respectively. The results on the scales were related to disease progression. Principal components factor analyses showed that the SOM scale could be divided into two subscales: dizziness/vertigo/anxiety and sensations in the ear. The PSYCHOL scale showed an energy/awareness factor and a negative emotional state factor. The SIT scale, finally, showed two factors: environmental disturbances and stressful conditions. CONCLUSIONS: Knowledge of somatic, psychological and situational premonitory characteristics of attacks in Ménière's disease could lead to improved therapy and counselling.     

Preoptic area and substantia nigra interact in the control of maternal behavior in the rat.

Investigated the influence of the lateral connections of the medial preoptic area (MPOA) on maternal behavior via the substantia nigra (SN). In Exp I, conducted with 45 postpartum lactating Charles River CD rats, the effects of large and small bilateral electrolytic lesions of SN were investigated. Large lesions severely disrupted maternal behavior and caused stereotyped activity in Ss. A 2nd experiment employed an asymmetrical lesion design and 37 Ss. Ss that received a unilateral knife cut severing the lateral connections of the MPOA and a contralateral lesion of the SN showed larger deficits in maternal behavior than either sham Ss or Ss that received a unilateral preoptic cut paired with an ipsilateral SN lesion. Measurements of body weights, body temperatures, and stereotyped behavior indicated that the differences in maternal behavior between the ipsilateral and contralateral groups could not be explained on the basis of nonspecific effects. (57 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Triazolam impairs inhibitory control of behavior in humans.

This study tested the effects of the sedative-hypnotic drug triazolam (Halcion) on the ability to inhibit behavior in humans. Thirty adults practiced a stop-signal task that measured their ability to inhibit and activate behavioral responses on a choice reaction time task. Equal numbers of participants (i.e., n?=?10) then received either 0.25 mg, 0.125 mg, or 0 mg (placebo) of triazolam under double-blind conditions and performed the task intermittently over a 3-hr period. In accord with the hypothesis, triazolam reduced response inhibitions and increased the time required to inhibit a response. The drug also slowed the activation of responses. The findings contribute to the understanding of the basic behavioral mechanisms by which sedative-hypnotic drugs can produce states of behavioral disinhibition in some individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Peripeduncular nucleus lesions in the rat: I. Effects on maternal aggression, lactation, and maternal behavior during pre- and postpartum periods.

Bilateral peripeduncular (PPN) lesions made on the 7th postpartum day (L7) with either radiofrequency (RF) current or N-methyl-d,l-aspartic acid (NMDA)/phosphate buffered saline (PBS) reduced maternal aggression (MA) and partially inhibited lactation without producing significant deficits in other items of maternal behavior (MB). RF-PPN lesions did not interfere with prolactin secretion, which suggests that there was deficient oxytocinergic activity. The deficit in MA was not due to interruption of afferent suckling input to the PPN: either thelectomizing females (Day L6) or producing bilateral knifecuts in the mesencephalon (placed caudal to the level of the PPN; Day L7) had no effect on MA, but both procedures impaired lactation. Deficits in MA produced by RF-PPN lesions developed gradually between Days L4 and L7; lesions made either prepartum or on Day L1 did not impair MA or MB. Deficits in lactation first appeared after RF-PPN lesions on Day L1. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oxytocin activates the postpartum onset of rat maternal behavior in the ventral tegmental and medial preoptic areas.

Oxytocin binding (Bmax) was found to be higher in the ventral tegmental area (VTA) and the medial preoptic area (MPOA) at midparturition compared with Pregnancy Days 15–27 or Postpartum Days 5–7 in rat dams. Pup retrieval and assuming a nursing posture over pups were blocked in parturient dams by infusions of an oxytocin antagonist into the VTA or MPOA and by infusions of a vasopressin (V?) antagonist into the MPOA. These results implicate oxytocin in the VTA and MPOA and vasopressin in the MPOA, as well as a parturition-associated rise in oxytocin binding in these sites in the postpartum activation of maternal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experience-dependent cell survival in the maternal rat brain.

Postpartum maternal experience produces long-lasting changes in maternal behavior in the mother rat, which can be altered by early-life isolation. Postpartum experience also affects the regulation of adult neurogenesis in the neural circuit underlying maternal behavior, in a region-specific manner. Female rats were reared either with their mothers (MR) or in isolation in an artificial rearing (AR) paradigm. In adulthood, rats were mated and separated from their pups at birth. The following day, dams were injected with a mitotic marker and either allowed to interact with pups (maternal experience) or left alone. Results show that MR rats that acquire a later maternal experience show increases in cell survival in parts of the excitatory limb of the maternal neural network (bed nucleus of the stria terminalis and nucleus accumbens), but no changes in the inhibitory limb (amygdala). In comparison to AR inexperienced rats, AR maternally experienced rats show no increases in cell survival in the excitatory limb, but a striking reduction in cell survival in the inhibitory limb. The results suggest that early preweaning maternal isolation alters the structural plasticity that occurs following a postpartum maternal experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Medial prefrontal cortex lesions in the female rat affect sexual and maternal behavior and their sequential organization.

Temporal sequences of sexual and maternal behaviors in female rats and their correlation with each other and with performance on a sensory-motor gating response inhibition task assessed by prepulse inhibition (PPI) were investigated following medial prefrontal cortex (mPFC) lesions. Following excitotoxic mPFC (n = 10) or sham (n = 9) lesions, sexual behaviors across the ovarian cycle were scored. After mating and parturition, maternal interactions were scored until pups reached postnatal Day 10. After resumption of the ovarian cycle, the female rats were tested for PPI. Compared with sham lesions, mPFC lesions impaired proceptive behaviors and some maternal behaviors (e.g., pup retrieval, pup licking) but did not affect others (e.g., nest building, pup mouthing). Lesions disrupted temporal sequences of solicitations (number of male orientations followed, within 4 s, by a level change) and pup retrievals (number of pup retrievals followed, within 5 s, by another retrieval). These sequential behavior patterns were significantly correlated with each other and with PPI. However, when PPI effects were partialled out, group differences were less strong, but persisted. This study demonstrated that mPFC manipulations affect actions rich in sequential structure in response to biologically relevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A circumplex model for maternal behavior.

"The purpose… is to demonstrate the generality of a social interaction conceptualization of maternal behavior by ordering the intercorrelation matrices of three sets of data on maternal behavior. When ordered both with factor analysis and with Guttman's circumplex model, similar two-dimensional organizations of maternal behavior concepts were found for the three sets of data." The 2 major dimensions of maternal behavior that can be isolated from all the studies are: love vs. hostility and autonomy vs. control. 16 refs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-licking deprivation and maternal behaviour in the primiparous rat.

Self-licking and/or collar licking was prevented in 25 female rats from the 21st day of age by means of a rubber collar about the neck. The ability of these Ss to deliver and maintain their litters did not differ from that of those whose collars did not restrict licking or from that of uncollared controls. This questions the hypothesis that preparturitive self-licking behavior is important for normal parturition and maternal behavior. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cocaine exposure prebreeding to weaning: maternal and offspring effects

1. The distribution of NADPH-diaphorase positive and catecholamine-containing nerve structures, and functional noradrenergic-nitrergic interactions, were studied in the rat anococcygeus muscle. 2. The morphological findings demonstrated NADPH-diaphorase positive neurons mostly as aggregates in intramural ganglia, nerve tracts and few single nerve fibres forming plexus-like structures. 3. The nitric oxide synthase inhibitor NG-nitro-L-arginine (L-NOARG) inhibited concentration-dependently the nitrergic relaxation, an effect reversed by L-arginine. The drug had dual effects on noradrenergic contractile responses: at lower concentrations (0.1-10 microM) it decreased the amplitude of contractions and this was not affected by L-arginine; higher concentrations (50-500 microM) potentiated the contractions, an effect that was prevented by L-arginine. 4. The electron acceptor, nitro blue tetrazolium (NBT) produced a rapid inhibition of the noradrenergic contractile responses (EC50 0.178 +/- 0.041 microM). The drug decreased the tone of the preparations. However, it potentiated concentration-dependently the nitrergic relaxations. 5. NBT (1 microM) had no significant effect on the relaxations induced by exogenously applied nitric oxide (NO)-donor sodium nitroprusside (SNP, 0.01-50 microM). However, the effect of NBT (0.1-10 microM) on the electrically induced relaxation was significantly decreased by L-NOARG (10 and 50 microM). The inhibition was of a non-competitive type. 6. Neither L-NOARG (100 microM) nor NBT (1 microM) had any effect on the spontaneous or electrically-induced release of 3H-radioactivity from the tissues preincubated in [3H]-noradrenaline. 7. It is concluded that L-arginine-NO pathway can modulate noradrenergic transmission in the rat anococcygeus muscle at postjunctional, but not prejunctional site(s).