We studied the neuronal basis of the motivational response to two powerful but radically different rewards-cocaine and maternal nurturing of pups in the postpartum rat (dam) which is in a unique motivational state. We used a place preference method designed to offer a choice between cues associated with a natural reinforcer (pups) and those associated with a pharmacologic reinforcer (cocaine). ...

Neuropeptide Y, a neuropeptide abundantly expressed in the brain, has been implicated in the regulation of the hypothalamo-pituitary-somatotropic axis and the hypothalamo-pituitary-gonadotropic axis. Elevated hypothalamic neuropeptide Y expression, such as that occurs during fasting, is known to inhibit both of these axes. However, it is not known which Y receptor(s) mediate these effects. Here...

Magnetoencephalography (MEG) is a relatively novel technique that allows the study of the dynamic properties of cortical activity. The functional localization of brain sources of MEG signals depends on the models used and it always has a certain degree of uncertainty. Nevertheless, MEG can be very useful in assisting the neurosurgeon in planning and carrying out brain surgery in, or around, elo...

Morphine significantly impairs maternal behavior; naloxone, an opiate antagonist, restores it. Maternal behavior is associated with c-fos expression, an immediate early gene product, in the medial preoptic area (mPOA) of females. In two experiments, the effects of morphine-alone and morphine plus naloxone on the expression of c-fos were examined. On postpartum day 5, females were injected with ...

Neuropeptides have widespread modulatory effects on behaviour and physiology and are associated with phenotypic transitions in a variety of animals. Arginine vasotocin (AVT) is implicated in mediating alternative male phenotypes in teleost fish, but the direction of the association differs among species, with either higher or lower AVT related to more territorial behaviour in different fishes. ...

While the survival value of paternal care is well understood, little is known about its physiological basis. Here we investigate the neuroendocrine contributions to paternal care in the monogamous cichlid, Amatitlania nigrofasciata. We first explored the dynamic range of paternal care in three experimental groups: biparental males (control fathers housed with their mate), single fathers (mate r...

Masahiro Konishi, Kazuyuki Kanosue, Masumi Kano, Akiko Kobayashi, and Kei Nagashima Department of Physiology, Course of Health Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; Department of Physiology, Faculty of Sports Sciences and Department of Integrative Physiology, Health and Welfare, Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama, Japan; Conso...

Exogenous growth hormone-releasing factor (GRF) has been shown to activate feeding by central mechanisms involving the suprachiasmatic nucleus/medial preoptic area (SCN/MPOA). Until now, however, the role played by endogenous GRF in the SCN/MPOA in naturally occurring eating has remained unknown. To investigate this, the effects of SCN/MPOA injections of GRF antiserum (AS-GRF) on feeding in rat...

Hamsters will spontaneously 'split' and exhibit two rest-activity cycles each day when housed in constant light (LL). The suprachiasmatic nucleus (SCN) is the locus of a brain clock organizing circadian rhythmicity. In split hamsters, the right and left SCN oscillate 12 h out of phase with each other, and the twice-daily locomotor bouts alternately correspond to one or the other. This unique co...

T HE EXISTENCE of temperature sensitive regions in the hypothalamus of the cat has been established (1-3). Though capable of controlling thermoregulatory effecters (central control), their relative importance in the unanesthetized animal as compared to the effect of afferent impulses (hereafter called ‘reflex control’), is not so clear. The present experiments were designed to determine a) whet...