The olfactory system of infant rats is not an immature version of the adult system but is organized to ensure infants form the attachment to the caregiver necessary for survival. We study a sensitive period during the first nine days of life when rat pups have unique learning abilities that ensure pups quickly and reliably learn a preference for the maternal odor that underlies pup orientation ...

PURPOSE Although hyperglycemia is likely the main stimulus for VEGF induction in diabetic retinopathy (DR), a switch from oral hypoglycemic therapy to parenteral insulin injection, despite producing better glucose control, sometimes paradoxically aggravates DR. The induction of VEGF by insulin, as observed in certain conditions, may be a plausible mechanism for this phenomenon. In the present s...

In this study, litters of rat pups and their mothers were continuously video-monitored from Day 14 to Day 35 postpartum in order to describe the behavioral changes that occur during that period. Prior to the onset of solid food intake (Day 18). pups spent most of their active time suckling. During Days 18 to 26, feeding, drinking, grooming, and play-fighting rapidly became frequent daily activi...

One-, 5-, and 11-day-old rats in a cool environment (25 degrees C) acquired an operant response when rewarded with a 20-s-long warming of the platform (from 25 to 36 degrees C) on which they lay. In Experiment 1, the head-turning response was learned by pups at all ages. When the contingency was reversed so that pups were reinforced for turning to the side opposite that correct during training,...

Rat pups become immobile and analgesic when exposed to an adult male rat. The aim of this study was to determine whether these reactions are under the control of endogenous opioids and to determine the role of the midbrain periaqueductal gray (PAG), which mediates stress-induced immobility and analgesia in adult animals. In Experiment 1, 14-day-old rats were injected systemically with the gener...

Otsuka Long-Evans Tokushima fatty (OLETF) rats are a strain of Long-Evans Tokushima Otsuka (LETO) rats that do not express CCK-1 receptors, developing in adulthood, hyperphagia, obesity, and non-insulin-dependent diabetes mellitus (NIDDM). We examined weight gain and meal patterns during a 30-min independent ingestion test on postnatal days 2-4 and again on days 9-11 in OLETF and LETO rat pups....

Supplemental Methods Neonatal ischemia-reperfusion. All experiments complied with ethical guidelines of Robert Debré Hospital Research Council Review Board (A75-19-01), INSERM and the ARRIVE guidelines (http://www.nc3rs.org/ARRIVE). Ischemia was induced in Wistar P7 rat pups (1618 g; Janvier, Le Genest St-Isle, France; both sexes) and was adapted to isoflurane anesthesia . Briefly, thermoregula...

Isolated rat pups respond to cold exposure physiologically by increasing metabolic heat production and behaviorally by emitting ultrasound. The relationship between these 2 responses was investigated by monitoring oxygen consumption, heat production by brown adipose tissue, respiratory rate, and ultrasound production during cold exposure in pups 10-12 days of age. All 3 physiological measures i...