Ultrastructure of the olfactory system of three newborn marsupial species

Gemmell, R. T.; Nelson, Jacob L.

doi:10.1002/ar.1092210211

Cited by 32 publications

(13 citation statements)

References 32 publications

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“…Our findings indicate that olfaction is unlikely to play a significant part in the guidance of the newborn wallaby to the pouch and nipple, refuting suggestions made by other authors [Gemmell and Nelson, 1988;Tyndale-Biscoe, 2005]. Although the olfactory epithelium has begun differentiation at the time of birth, there are several key functionally important aspects of maturation of the olfactory epithelium and central olfactory pathways which do not develop until well into the first postnatal week or even later.…”

Section: Does Olfaction Play a Part In Guidance Of The Newborn Tammarcontrasting

confidence: 43%

“…This naturally raises the question regarding which sensory pathways are sufficiently mature to assist with this task. The other candidate sensory system, which would logically be considered for this role, is the trigeminal somatosensory system [Gemmell and Nelson, 1988;Hughes et al, 1989]. Even though the developing vibrissal follicles consist of only solid epidermal plugs surrounded by dermal condensations at birth, these structures are innervated by afferents of the maxillary division of the tri-geminal nerve [Waite et al, 1994].…”

Section: Does Olfaction Play a Part In Guidance Of The Newborn Tammarmentioning

confidence: 99%

“…The manner in which the newborn tammar redirects its movements when it reaches the edge of the pouch and enters it might indicate a response to either the odor of the pouch or the texture of its moist hairless skin [Tyndale-Biscoe, 2005]. Olfactory knobs have been identified in the nasal epithelium of the newborns of several species of diprotodont and polyprotodont marsupials [Gemmell and Nelson, 1988;Gemmell and Rose, 1989;Gemmell and Selwood, 1994] and well-developed nerve fibers have been shown to connect the olfactory epithelium to the relatively large olfactory bulbs at birth in the native cat and the tammar [Hill and Hill, 1955;Hassiotis et al, 2002]. These findings stand in contrast to the delayed development of neuronal activity in the olfactory bulb of the tammar, investigated in vivo under anesthesia [Ellendorff et al, 1988].…”

Section: Introductionmentioning

confidence: 99%

“…Considerable attention has been given to the study of the development of the olfactory system and its central projections in Ameridelphids such as Didelphis and Monodelphis [Lin et al, 1988;Schwanzel-Fukuda et al, 1988;Brunjes et al, 1992;Malun and Brunjes, 1996;Chuah et al, 1997;Couper Leo and Brunjes, 1999], but study of the development of the olfactory system in Australian diprotodont marsupials (including macropods and phalangerids) has been largely confined to the olfactory epithelium [Gemmell and Nelson, 1988;Gemmell and Rose, 1989]. Nothing is known at present about the timing of the anatomical development of central olfactory connections in Australian marsupials; particularly with regard to the possible role of olfaction in the critically important survival behavior of newborn tammars.…”

Section: Introductionmentioning

confidence: 99%

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Development of the Olfactory System in a Wallaby <i>(Macropus eugenii)</i>

Ashwell¹,

Marotte

Cheng³

2008

Brain Behav Evol

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We used carbocyanine dye tracing techniques in conjunction with hematoxylin and eosin staining, immunohistochemistry for GAP-43, and tritiated thymidine autoradiography to examine the development of the olfactory pathways in early pouch young tammar wallabies (Macropus eugenii). The overarching aim was to test the hypothesis that the olfactory system of newborn tammars is sufficiently mature at birth to contribute to the guidance of the pouch young to the nipple. Although GAP-43 immunoreactive fibers emerge from the olfactory epithelium and enter the olfactory bulb at birth, all other components of the olfactory pathway in newborn tammars are very immature at birth, postnatal day (P0). In particular, maturation of the vomeronasal organ and its projections to the accessory olfactory bulb appears to be delayed until P5 and the olfactory bulb is poorly differentiated until P12, with glomerular formation delayed until P25. The lateral olfactory tract is also very immature at birth with pioneer axons having penetrated only the most rostral portion of the piriform lobe. Interestingly, there were some early (P0) projections from the olfactory epithelium to the medial septal region and lamina terminalis (by the terminal nerve) and to olfactory tubercle and basal forebrain. The former of these is presumably serving the transfer of LHRH⁺ neurons to the forebrain, as seen in eutherians, but neither of these very early pathways is sufficiently robust or connected to the more caudal neuraxis to play a role in nipple finding. Tritiated thymidine autoradiography confirmed that most piriform cortex pyramidal neurons are generated in the first week of life and are unlikely to be able to contribute to circuitry guiding the climb to the pouch. Our findings lead us to reject the hypothesis that olfactory projections contribute to guidance of the newborn tammar to the pouch and nipple. It appears far more likely that the trigeminal pathways play a significant role in this behavior because the central projections of the trigeminal nerve are more mature at birth in this marsupial.

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Section: Does Olfaction Play a Part In Guidance Of The Newborn Tammarcontrasting

confidence: 43%

Section: Does Olfaction Play a Part In Guidance Of The Newborn Tammarmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Development of the Olfactory System in a Wallaby <i>(Macropus eugenii)</i>

Ashwell¹,

Marotte

Cheng³

2008

Brain Behav Evol

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“…Thus the terminal, vomeronasal, olfactory, optic, oculomotor, trochlear and abducens, would not be functional. Even though there are olfactory receptors (Gemmell and Nelson 1988c) there is no organisation within the telencephalon or diencephalon to enable a connection to a motor centre. The newborn thus depends on the trigeminal, facial, vestibular [see Gemmell and Nelson 1989], glossopharyngeal, vagus, accessory and hypoglossal but not auditory.…”

Section: Discussionmentioning

confidence: 99%

Developmental staging in a marsupial Dasyurus hallucatus

Nelson

1992

Anat Embryol

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In a marsupial, Dasyurus hallucatus, pouch-young of various ages from newborn to 55 days were embedded in wax and serially sectioned. On the basis of the relative development of external and internal characteristics, they were placed in the Carnegie staging system developed by Streeter and elaborated by O'Rahilly and associates. Birth occurred at stage 15, and the end of embryogenesis (stage 23) was reached about day 33. Whereas stage 23 is characterised in all eutherians by the closure of the secondary palate, this occurs before stage 15 in D. hallucatus. Since most other characters of the newborn are at a stage 15 level of development, there has been a relative acceleration of development of the secondary palate (and forelimb) in D. hallucatus that allows it to suckle and breathe at the same time. Between D. hallucatus and eutherians, there is general agreement in the sequence of development and in the relative degree of most structures at each stage. Further marsupials should be examined to see if the minor differences noted are peculiar to D. hallucatus or apply to marsupials generally.

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Vestibular system of the newborn marsupial cat Dasyurus hallucatus

Gemmell

Nelson

1989

Anat. Rec.

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The ultrastructure of the ear of the newborn native cat was examined to determine whether the vestibular system contained sensory receptors. A sensory region, presumably the utricle, was identified in each ear and consisted of a discrete population of otoliths overlying a sensory epithelium which possessed kinocilia and stereocilia. The remainder of the vestibular system did not appear to be developed anatomically. The newborn cat has rudimentary vestibular, olfactory, and mechanoreceptors (Merkel cells), and these structures may aid the newborn marsupial in the journey from the urogenital sinus to the pouch and in locating the teat.

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Ultrastructure of the olfactory system of three newborn marsupial species

Cited by 32 publications

References 32 publications

Development of the Olfactory System in a Wallaby <i>(Macropus eugenii)</i>

Development of the Olfactory System in a Wallaby <i>(Macropus eugenii)</i>

Developmental staging in a marsupial Dasyurus hallucatus

Vestibular system of the newborn marsupial cat Dasyurus hallucatus

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