Facial musculature, nerves and blood vessels of the hamster in relation to the cheek pouch

Priddy, Ralph B.; Brodie, Arnold F.

doi:10.1002/jmor.1050830202

Cited by 40 publications

(24 citation statements)

References 9 publications

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“…In preparation for surgical manipulations and to confirm literature descriptions of pouch anatomy (Van Hoosier and McPherson, 1987), particularly with respect to functional and morphological relationships between retractor and pouch (Priddy and Brodie, 1948), we began with dissections of male and female specimens of Mesocricetus auratus Waterhouse with full and empty pouches. We used the video apparatus described below to observe chewing and pouching behavior in intact and then unilaterally retractor-denervated (cranial nerve XI) hamsters.…”

Section: Methodsmentioning

confidence: 99%

“…We have shown that the retractor muscle, regionally distinct from the feeding apparatus in Syrian hamsters, and previously thought to provide only structural support or to function in pouch emptying (Priddy and Brodie, 1948), actually cooperates with jaw musculature to accomplish the goal of filling the cheek pouch. The cheek pouch is an oblong, thin-walled sac with very few longitudinal muscle fibers in the lateral wall.…”

Section: The Role Of the Retractor Musclementioning

confidence: 97%

“…The anatomy of internal and external cheek pouches has been described in detail elsewhere (Priddy and Brodie, 1948;Ryan, 1986;Ryan, 1989), and other authors have speculated on the relationship between cheek pouch form and function in rodents (Keyes andDale, 1944, Long, 1976). In Syrian hamsters, cheek pouch function has been examined using electromyographic stimulation (Priddy and Brodie, 1948) and videotaping (Gorniak, 1977), but jaw activity and the role of the retractor muscle in pouch filling have not been described.…”

Section: Prodigious Food Hoarding In Syrian Hamstersmentioning

confidence: 99%

“…In Syrian hamsters, cheek pouch function has been examined using electromyographic stimulation (Priddy and Brodie, 1948) and videotaping (Gorniak, 1977), but jaw activity and the role of the retractor muscle in pouch filling have not been described. One externally pouched rodent, Dipodomys deserti, has been shown to coordinate forelimb activity with one jaw cycle per pouching event, defined as the insertion of one load of food from paws into cheek pouches (Nikolai and Bramble, 1983).…”

Section: Prodigious Food Hoarding In Syrian Hamstersmentioning

confidence: 99%

“…This observation was perplexing in that the retractor is not ideally positioned to play a role in pouch filling, nor has it ever been proposed to do so. Generally, it has been construed as structural support, acting as an 'antagonist to the longitudinal musculature of the pouch wall' (Priddy and Brodie, 1948). When Priddy and Brodie applied electrical stimulation to the facial nerve innervating the pouch wall muscles while observing the location of a pea placed inside the pouch, the pea moved toward the pouch opening and in some cases, into, but not through the opening.…”

Section: Prodigious Food Hoarding In Syrian Hamstersmentioning

confidence: 99%

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Kinematic analysis of an appetitive food-handling behavior: the functional morphology of Syrian hamster cheek pouches

Buckley

Schneider

Cundall

2007

Journal of Experimental Biology

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SUMMARY Prodigious food hoarding in Syrian hamsters Mesocricetus auratusWaterhouse is strongly linked to appetite and is made possible by large internal cheek pouches. We provide a functional analysis of the cheek pouch and its associated retractor muscle. Frame-by-frame analysis of videotaped pouch-filling behavior revealed multiple jaw cycles for each food item pouched and the use of more jaw cycles to pouch large food items (∼2.5 g chow pellets) than small (corn kernels or sunflower seed with husks). These results stand in contrast to previously reported pouching kinematics in the externally pouched Dipodomys deserti, which uses only one jaw cycle per pouching event. Comparison of pouching and mastication in the same individuals also suggests that in Syrian hamsters, feeding jaw cycles are modulated to accommodate pouch filling primarily by the addition of a pause between fast open and fast close phases, which we call `gape phase'. Contrary to previous assertions, the retractor muscle does not merely provide structural support for the full pouch during locomotion. Video analysis of ten hamsters with unilaterally denervated retractor muscles and electrophysiological study of an anaesthetized subject confirmed that retractor muscle activity during pouch filling increases pouching efficiency for food items subsequent to the first.

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Section: Methodsmentioning

confidence: 99%

Section: The Role Of the Retractor Musclementioning

confidence: 97%

Section: Prodigious Food Hoarding In Syrian Hamstersmentioning

confidence: 99%

Section: Prodigious Food Hoarding In Syrian Hamstersmentioning

confidence: 99%

Section: Prodigious Food Hoarding In Syrian Hamstersmentioning

confidence: 99%

See 3 more Smart Citations

Kinematic analysis of an appetitive food-handling behavior: the functional morphology of Syrian hamster cheek pouches

Buckley

Schneider

Cundall

2007

Journal of Experimental Biology

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Comparative myology of the forelimb of squirrels (Sciuridae)

1997

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The musculature of the shoulder, arm, and forearm was studied in 19 genera of squirrels, representing the Pteromyinae (flying squirrels) and all 7 tribes of the Sciurinae (tree and ground squirrels). The objective was to locate derived anatomical features of functional or phylogenetic significance and to determine how much morphological variation underlies the diverse locomotor behavior of squirrels, which includes terrestrial and arboreal bounding, climbing, digging, and gliding. The fossil evidence suggests that arboreality is primitive for squirrels, and in fact tree squirrels appear to represent the primitive sciurid morphology. Ground squirrels are less uniform and exhibit a few derived features, including a clavobrachialis muscle not seen in other squirrels. Pygmy tree squirrels, which have evolved independently in three tribes, exhibit convergence of forelimb anatomy, including the loss or reduction of several muscles in the shoulder and forearm. The forelimb anatomy of flying squirrels is the most derived and differs from that of tree squirrels in details of shoulder, arm, and forearm musculature. Some of these muscular differences among squirrels have phylogenetic significance, being shared by closely related genera, but none has significance above the tribal level. Many of the differences suggest a variety of changes in function that are amenable to further study.

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Motor nerve topology reflects myocyte morphology in hamster retractor and epitrochlearis muscles

2000

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Neuromuscular activation is a primary determinant of metabolic demand and oxygen transport. The m. retractor and m. epitrochlearis are model systems for studying metabolic control and oxygen transport; however, the organization of muscle fibers and motor nerves in these muscles is unknown. We tested whether the topology of motor innervation was related to the morphology of muscle fibers in m. retractor and m. epitrochlearis of male hamsters (∼100 g). Respective muscles averaged 47 and 12 mm in length 100 and 35 mg in mass. Staining for acetylcholinesterase revealed neuromuscular junctions arranged in clusters throughout m. retractor and as a central band across m. epitrochlearis, suggesting differences in fiber morphology. For both muscles, complete cross‐sections contained ∼1,700 fibers. Fiber cross‐sectional areas were distributed nearly normal in m. epitrochlearis (mean = 1,559 ± 17 μm2) and skewed left (P < 0.05) in m. retractor (mean = 973 ± 15 μm2). Single fiber length (Lf) spanned muscle length (Lm) in m. epitrochlearis, while fibers tapered to terminate within m. retractor (Lf/Lm = 0.43 ± 0.02). With myelin staining, a single branch of ulnar nerve projected axons across the midregion of m. epitrochlearis. For m. retractor, the spinal accessory nerve branched to give rise to proximal and distal regions of innervation, with intermingling of axons between nerve branches. Nerve bundle cross‐sections stained for acetylcholinesterase indicate that each motor axon projects to an average of 65 muscle fibers in m. epitrochlearis and 100 in m. retractor. Differences in fiber morphology, innervation topology, and neuromuscular organization may contribute to the heterogeneity of metabolic demand and oxygen supply in skeletal muscle. J. Morphol. 246:103–117, 2000 © 2000 Wiley‐Liss, Inc.

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Facial musculature, nerves and blood vessels of the hamster in relation to the cheek pouch

Cited by 40 publications

References 9 publications

Kinematic analysis of an appetitive food-handling behavior: the functional morphology of Syrian hamster cheek pouches

Kinematic analysis of an appetitive food-handling behavior: the functional morphology of Syrian hamster cheek pouches

Comparative myology of the forelimb of squirrels (Sciuridae)

Motor nerve topology reflects myocyte morphology in hamster retractor and epitrochlearis muscles

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