Centrifugal projections to the main olfactory bulb revealed by transsynaptic retrograde tracing in mice.

A wide range of evidence indicates that olfactory perception is strongly involved in food intake. However, the polysynaptic circuitry linking the brain areas involved in feeding behavior to the olfactory regions is not well known. The aim of this article was to examine such circuits.

Somatostatin Serves a Modulatory Role in the Mouse Olfactory Bulb: Neuroanatomical and Behavioral Evidence.

Somatostatin (SOM) and somatostatin receptors (SSTR1-4) are present in all olfactory structures, including the olfactory bulb (OB), where SOM modulates physiological gamma rhythms and olfactory discrimination responses. In this work, histological, viral tracing and transgenic approaches were used to characterize SOM cellular targets in the murine OB. We demonstrate that SOM targets all levels of mitral dendritic processes in the OB with somatostatin receptor 2 (SSTR2) detected in the dendrites of previously uncharacterized mitral-like cells.

Brain anatomy of the 4-day-old European rabbit.

The European rabbit (Oryctolagus cuniculus) is a widely used model in fundamental, medical and veterinary neurosciences. Besides investigations in adults, rabbit pups are relevant to study perinatal neurodevelopment and early behaviour. To date, the rabbit is also the only species in which a pheromone - the mammary pheromone (MP) - emitted by lactating females and active on neonatal adaptation has been described.

Morphology and evolution of the oral shield in marsupial neonates including the newborn monito del monte (Dromiciops gliroides, Marsupialia Microbiotheria) pouch young.

Newborn marsupials can be arranged into three grades of developmental complexity based on their external form, as well as based on their organ systems and their cytology. The dasyurids are considered the least developed marsupials at birth, while didelphids and peramelids are intermediate, and macropods are the most developed. Currently there is still little information on caenolestid and microbiotherid development at birth.

Spontaneous brain processing of the mammary pheromone in rabbit neonates prior to milk intake.

Chemical signals play a critical role in interindividual communication, including mother-young relationships. Detecting odor cues released by the mammary area is vital to the newborn's survival. European rabbit females secret a mammary pheromone (MP) in their milk, which releases sucking-related orocephalic movements in newborns.

Brain processing of a configural vs elemental odor mixture in the newborn rabbit.

Organisms are surrounded throughout life by chemically complex odors. How individuals process an odorant within a mixture or a mixture as a whole is a key question in neuroethology and chemical senses. This question is addressed here by using newborn rabbits, which can be rapidly conditioned to a new stimulus by single association with the mammary pheromone.

Taste preferences.

Personal experience, learned eating behaviors, hormones, neurotransmitters, and genetic variations affect food consumption. The decision of what to eat is modulated by taste, olfaction, and oral textural perception. Taste, in particular, has an important input into food preference, permitting individuals to differentiate nutritive and harmful substances and to select nutrients.

Goα expression in the vomeronasal organ and olfactory bulb of the tammar wallaby.

The vomeronasal organ (VNO) detects pheromones via 2 large families of receptors: vomeronasal receptor 1, associated with the protein Giα2, and vomeronasal receptor 2, associated with Goα. We investigated the distribution of Goα in the developing and adult VNO and adult olfactory bulb of a marsupial, the tammar wallaby. Some cells expressed Goα as early as day 5 postpartum, but by day 30, Goα expressing cells were distributed throughout the receptor epithelium of the VNO.

Identification of two distinct genes at the vertebrate TRPC2 locus and their characterisation in a marsupial and a monotreme.

Background: The vomeronasal organ (VNO) detects pheromones via two large families of vomeronasal receptors: vomeronasal receptor 1 (V1R) and vomeronasal receptor 2 (V2R). Both VRs have a common receptor activation cascade involving transient receptor potential channel, subfamily C, member 2 (TRPC2).

Results: We characterised the TRPC2 locus in a marsupial, the tammar wallaby (Macropus eugenii), and identified two independently regulated genes not previously recognised as distinct.

Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development.

Background: We present the genome sequence of the tammar wallaby, Macropus eugenii, which is a member of the kangaroo family and the first representative of the iconic hopping mammals that symbolize Australia to be sequenced. The tammar has many unusual biological characteristics, including the longest period of embryonic diapause of any mammal, extremely synchronized seasonal breeding and prolonged and sophisticated lactation within a well-defined pouch. Like other marsupials, it gives birth to highly altricial young, and has a small number of very large chromosomes, making it a valuable model for genomics, reproduction and development.

The development of the olfactory organs in newly hatched monotremes and neonate marsupials.

Olfactory cues are thought to play a crucial role in the detection of the milk source at birth in mammals. It has been shown that a marsupial, the tammar wallaby, can detect olfactory cues from its mother's pouch at birth. This study investigates whether the main olfactory and accessory olfactory system are similarly well developed in other marsupials and monotremes at birth/hatching as in the tammar.

The effect of pregnant and oestrous females on male testosterone and behaviour in the tammar wallaby.

Tammar wallaby females (Macropus eugenii) are seasonally breeding marsupials with a post-partum oestrus after a highly synchronised birth period when testosterone concentrations rise in males. Chemical communication appears to be important for mating, as males show checking behaviour, sniffing the urogenital opening (UGO) and the pouch of females. This study investigates whether the presence of pregnant and oestrous females directly influences testosterone in males and if oestrous odours or secretion from the pouch or UGO are attractive.

The olfactory system of the tammar wallaby is developed at birth and directs the neonate to its mother's pouch odours.

In kangaroos and wallabies at birth the highly altricial newborn young climbs unassisted from the urogenital opening to the teat. Negative geotropism is important for the initial climb to the pouch opening, but nothing is known of the signals that then direct the neonate downwards to the teat. Here we show that the newborn tammar wallaby (Macropus eugenii) has the olfactory apparatus to detect smell.

The vomeronasal organ of the tammar wallaby.

The vomeronasal organ is the primary olfactory organ that detects sexual pheromones in mammals. We investigated the anatomy of the vomeronasal organ of the tammar wallaby (Macropus eugenii), a small macropodid marsupial. Pheromones may be important for activation of the hypothalamo-pituitary axis of tammar males at the start of the breeding season because plasma testosterone and luteinizing hormone concentration in males rise concurrently with pregnancy and the post-partum ovulation in females.