A new gustometer for taste testing in rodents.

In recent years, to circumvent the interpretive limitations associated with intake tests commonly used to assess taste function in rodents, investigators have developed devices called gustometers to deliver small volumes of taste samples and measure immediate responses, thereby increasing confidence that the behavior of the animal is under orosensory control. Most of these gustometers can be used to measure unconditioned licking behavior to stimuli presented for short durations and/or can be used to train the animal to respond to various fluid stimuli differentially so as to obtain a reward and/or avoid punishment. Psychometric sensitivity and discrimination functions can thus be derived.

AKT signaling within the ventral tegmental area regulates cellular and behavioral responses to stressful stimuli.

Background: The neurobiological mechanisms by which only a minority of stress-exposed individuals develop psychiatric diseases remain largely unknown. Recent evidence suggests that dopaminergic neurons of the ventral tegmental area (VTA) play a key role in the manifestation of stress vulnerability.

Methods: Using a social defeat paradigm, we segregated susceptible mice (socially avoidant) from unsusceptible mice (socially interactive) and examined VTA punches for changes in neurotrophic signaling.

Antidepressant treatment can normalize adult behavioral deficits induced by early-life exposure to methylphenidate.

Background: Methylphenidate (MPH) is prescribed for the treatment of attention-deficit/hyperactivity disorder. Exposure to MPH before adulthood causes behavioral deficits later in life, including anxiety- and depression-like behaviors and decreased responding to natural and drug rewards. We examined the ability of fluoxetine (FLX), a selective serotonin reuptake blocker, to normalize these MPH-induced behavioral deficits.

Ovarian steroid hormones modulate circadian rhythms of neuroendocrine dopaminergic neuronal activity.

Dopamine (DA) is the primary inhibitor of prolactin (PRL) secretion. Three populations of neuroendocrine dopaminergic neurons (NDNs) designated tuberoinfundibular (TIDA), tuberohypophyseal (THDA) and periventricular hypophyseal DAergic (PHDA) neurons regulate PRL secretion. Given that ovarian steroids modulate both DA release and PRL secretion independently, we characterized the role of steroid hormones in coupling rhythmic NDN activity and PRL secretion.