Nitrergic Neurons in the Spinal Cord of the Bottlenose Dolphin (Tursiops truncatus)

Nitric oxide (NO) is a freely diffusible gaseous neurotransmitter generated by a selected population of neurons and acts as a paracrine molecule in the nervous system. NO is synthesized from l ‐arginine by means of the neuronal nitric oxide synthase (nNOS), an enzyme requiring nicotine adenine dinucleotide phosphate (NADPH) as cofactor. In this study, we used histochemical and immunohistochemical techniques to investigate the distribution of NADPH‐diaphorase (NADPH‐d) and nNOS in the spinal cord of the bottlenose dolphin (Tursiops truncatus). Cells with a fusiform‐shaped somata were numerous in the laminae I and II. The intermediolateral horn showed darkly‐stained cells with a multipolar morphology. Neurons with a multipolar or fusiform morphology were observed in the ventral horn. Multipolar and fusiform neurons were the most common cell types in lamina X. Nitrergic fibers were numerous especially in the dorsal and intermediolateral horns. The presence of nitrergic cells and fibers in different laminae of the spinal cord suggests that NO may be involved in spinal sensory and visceral circuitries, and potentially contribute to the regulation of the complex retia mirabilia. Anat Rec, 296:1603–1614, 2013. © 2013 Wiley Periodicals, Inc.     

Distribution of Nitrergic Neurons in the Dorsal Root Ganglia of the Bottlenose Dolphin (Tursiops truncatus)

Dorsal root ganglia (DRGs) contain the cell bodies of primary afferent neurons that transmit sensory information from the periphery into the spinal cord. Distinct populations of DRG neurons have been characterized by a variety of different immunohistochemical markers. A subpopulation of ganglionic neurons containing neuronal nitric oxide synthase (nNOS), an enzyme known to generate nitric oxide, has been detected in a number of mammalian species. Despite previous studies, no information is known on the presence and exact distribution of nNOS‐immunoreactive neurons in the DRGs of the bottlenose dolphin. In this investigation, immunoperoxidase for nNOS was used to determine the distribution and the perikaryal size of nitrergic neurons in the DRGs of this species. Double immunofluorescence protocol was used to determine the percentage of nNOS‐immunoreactive (IR) neurons over the total primary afferent neurons. In addition, double immunostaining was used to verify whether there was colocalization of nNOS with substance P (SP). In all DRGs, a subpopulation of small‐ and medium‐sized neurons (about 9%) exhibited nNOS immunoreactivity. Data analysis revealed that the majority of nNOS‐IR neurons (81.3%) expressed SP. The density of nNOS‐immunoreactive and nNOS/SP‐double immunopositive cells was relatively constant throughout the ganglia. However, as observed in others mammals, the number of nitrergic neurons decreased in the caudalmost DRGs. Our results, in conjunction with previous observations, suggest that nNOS‐IR neurons may be involved in the afferent transmission of visceral and nociceptive information as well as in the regulation of the vascular tone. Anat Rec,, 2011. © 2011 Wiley‐Liss, Inc.     

Immunohistochemical Localization of Substance P And Cholecystokinin in the Dorsal Root Ganglia and Spinal Cord of the Bottlenose Dolphin (Tursiops truncatus)

The presence of substance P (SP) and cholecystokinin (CCK) immunoreactive neurons was examined in the bottlenose dolphin dorsal root ganglia (DRGs) and spinal cord by immunohistochemical techniques. SP‐positive and CCK‐immunoreactive neurons were respectively ～50% and 1% of the total number of ganglion cells examined and especially belonged to small and medium‐sized cell populations. Using double labeling techniques we observed that SP‐ and CCK‐immunoreactivity coexisted in a very low number of primary afferent neurons (2.7%). Few SP‐immunoreactive (IR) neurons (2.7%) were also CCK‐positive. On the contrary, 65% of CCK‐immunoreactive neurons contained SP. Interestingly, we observed CCK‐immunoreactive satellite glial cells located around large cell class somata. Virtually no SP‐IR and CCK‐positive neurons were surrounded by peripheral CCK‐immunoreactive satellite glial cells. The SP‐IR and CCK‐positive nerve fibers were particularly conspicuous in the superficial layers of the spinal cord. The present study indicates that SP and CCK only partially overlap in the thoracic, lumbar, and caudal DRGs of the bottlenose dolphin, suggesting that the majority of SP‐IR ganglion neurons are lacking in CCK‐immunoreactivity. The role of SP‐containing DRG neurons is discussed also in relation to the huge vascular spinal retia mirabilia typical of cetaceans. Anat Rec, 293:477–484, 2010. © 2010 Wiley‐Liss, Inc.     

Female Reproductive Tract Immunity in Bovine Trichomoniasis

PROBLEM: Mechanisms of protective immunity in the female reproductive tract are poorly understood. For sexually transmitted diseases, bovine trichomoniasis is a useful model because il resembles human trichomoniasis to some extent, and antibodies play an important role in protection against these extracellular parasites. Protective efficacy was compared in animals with genital responses of predominantly immunoglobulin G (IgG) or predominantly IgA antibodies to a purified surface antigen of Tritrichomonas foetus. METHOD OF STUDY: Immunization of mice by various routes with immunoaffinity-purified T. foetus surface antigen (TF1.17) or killed cells was used to define the best routes and antigen combinations to give predominantly IgG or IgA antibodies to TF1.17 antigens in genital secretions. Cattle were then immunized either subcutaneously (SC) two times with TF1.17 antigen and once SC with killed T. foetus or twice SC with TF1.17 antigen and once intravaginally with killed T. foetus. All immunizations were in Quil A adjuvant. Controls were not immunized. Animals were challenged intravaginally with 10⁶ T. foetus 3 weeks after the third immunization. Vaginal mucus was collected weekly for culture and antibody assays. Serum was collected weekly, and uterine secretions were collected at 10 weeks post-challenge. Tissues were fixed at 10 weeks also. RESULTS: Murine studies showed systemic priming with vaginal boosting gave the highest genital IgA responses. In cattle, systemic immunization (group S) induced high IgG1 antibody levels in vaginal secretions. Systemic priming with vaginal boosting (group S/V) primed for an anamnestic vaginal IgA response after challenge with T. foetus. Cattle with predominantly IgG or predominantly IgA responses in vaginal secretions either did not become infected or cleared infection faster than controls. Uterine IgA responses at 10 weeks were highest in the vaginally boosted group, but other responses were not different from the controls at this time point. Microscopic examination of genital tissues showed subepithelial infiltration of mononuclear cells in all groups. Lymphoid aggregates or nodules were detected in vaginal sections in cattle of groups S/V and C as well as in uterine sections of all animals in all three groups. CONCLUSIONS: Both IgG and IgA antibodies to T. foetus superficial antigen were associated with protection. The timing of the response was related to the time of clearance. Lymphoid organization in the vagina and uterine tissues suggested development of mucosal inductive sites.     

Computed Tomography and Cross‐Sectional Anatomy of the Thorax of the Live Bottlenose Dolphin (Tursiops truncatus)

Pulmonary disease is one of the leading causes of cetacean morbidity and mortality in the wild and in managed collections. The purpose of this study was to present the computed tomographic (CT) appearance of the thorax of the live bottlenose dolphin (Tursiops truncatus) out‐of‐water and to describe the technical and logistical parameters involved in CT image acquisition in this species. Six thoracic CT evaluations of four conscious adult bottlenose dolphins were performed between April 2007 and May 2012. Animals were trained to slide out of the water onto foam pads and were transported in covered trucks to a human CT facility. Under light sedation, animals were secured in sternal recumbency for acquisition of CT data. Non‐contrast helical images were obtained during an end‐inspiratory breath hold. Diagnostic, high quality images were obtained in all cases. Respiratory motion was largely insignificant due to the species' apneustic respiratory pattern. CT findings characteristic of this species include the presence of a bronchus trachealis, absence of lung lobation, cranial cervical extension of the lung, lack of conspicuity of intrathoracic lymph nodes, and presence of retia mirabilia. Dorsoventral narrowing of the heart relative to the thorax was seen in all animals and is suspected to be an artifact of gravity loading. Diagnostic thoracic computed tomography of live cetaceans is feasible and likely to prove clinically valuable. A detailed series of cross‐sectional reference images is provided. Anat Rec, 297:901–915, 2014. © 2014 Wiley Periodicals, Inc.     

Expression and Immunohistochemical Detection of Leptin‐Like Peptide in the Gastrointestinal Tract of the South American Sea Lion (Otaria flavescens) and the Bottlenose Dolphin (Tursiops truncatus)

This study provides an immunohistochemical approach to the expression of leptin in the gastrointestinal tract of the monogastric South American sea lion (Otaria flavescens), and the poligastric bottlenose dolphin (Tursiops truncatus). The specific organization of the gastrointestinal tract is examined in relation to the neuroendocrine regulation of the gut exerted by leptin. In the South American sea lion some leptin‐like‐immunoreactive (ir) cells, and endocrine type cells, were found in the pit of gastric mucosal folds and in the epithelium of duodenum as well as numerous neurons were detected in the submucosal and myenteric plexuses of the stomach. In the bottlenose dolphin, many leptin‐like‐ir cells, and exocrine type cells, were identified in the mucosal layer of the main stomach as well as several neurons and nervous fibers were detected in nervous plexuses of main stomach, pyloric stomach, proximal, and middle intestine. Our data suggest that the distribution of leptin‐like peptides is similar in the two species, notwithstanding the different anatomical organization of the gastrointestinal apparatus of South American sea lion and bottlenose dolphin. These findings “suggest” the presence of a basal plan in the regulation of food intake, body weight, energy balance and of the gastrointestinal functions in general also in marine mammals with different and specific feeding habits. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Secretory Immunity in the Female Reproductive Tract

PROBLEM: Antibodies and antibody-producing cells display a different and characteristic distribution in body fluids and tissues. METHOD: We have investigated the tissues of the female reproductive tract to determine whether the distribution of immunoglobulin-producing cells and the contents of cervical secretions were similar to those found in tissues of the secretory immune system. RESULTS: Immunohistochemical examinations of female genital tissues revealed the presence of plasma cells that secrete IgA (and in lower numbers IgM and IgG) especially in the subepithelial layers of the uterine endo- and ectocervix, fallopian tubes, and vagina. Both IgA1- and IgA2-producing plasma cells were found in approximately equal proportions. The presence of J-chain in the IgA-secreting cells suggests the synthesis of polymeric IgA (plgA). Epithelial cells lining the fallopian tube and endocervix were positive for secretory component (SC), which is required for the transepithelial transport of pIgA into external secretions. Cervical mucus was collected and the molecular forms of IgA were separated using column chromatography. Approximately 80% of IgA in cervical mucus was polymeric compared with 55% in the vaginal fluid. CONCLUSIONS: These data indicate that all effector components of the mucosal immune system are present in the female reproductive tract. The immunization routes that lead to a secretory IgA (S-IgA) response need to be further explored.     

Age estimation in the Mediterranean bottlenose dolphin Tursiops truncatus (Montagu 1821) by bone density of the thoracic limb

The determination of age is an important step in defining the life history traits of individuals and populations. Age determination of odontocetes is mainly based on counting annual growth layer groups in the teeth. However, this useful method is always invasive, requiring the cutting of at least one tooth, and sometimes the results are difficult to interpret. Based on the concept that bone matrix is constantly deposited throughout life, we analysed the bone mineral density of the arm and forearm of a series of bottlenose dolphins (Tursiops truncatus, Montagu 1821) stranded along the Italian coast of the Adriatic Sea or maintained in confined waters. The bone mineral density values we obtained were evaluated as possible age predictors of the Mediterranean population of this species, considering age as determined by counting growth layer groups in sections of the teeth and the total body length of the animal as references. Comparisons between left and right flipper showed no difference. Our results show that bone mineral density values of the thoracic limb are indeed reliable age predictors in Tursiops truncatus. Further investigations in additional odontocete species are necessary to provide strong evidence of the reliability of bone mineral density as an indicator of growth and chronological wear and tear in toothed-whales.     

Morphology of the complex laryngeal gland in the Atlantic Bottlenose dolphin,Tursiops truncatus

A complex lymphoepithelial gland is a constant feature in the larynx of Atlantic bottlenose dolphins, Tursiops truncatus, based on study of 56 animals. Larynges were removed from fresh, non‐decomposed beach‐stranded animals for gross examination and histological sampling. A large lymphoepithelial gland occurs in the rostro‐ventral mucosa of the larynx, overlying the cricoid cartilage. It presents as a well‐defined, elevated, and heavily trabeculated area. Histological examination reveals a pseudostratified columnar epithelium which branches into the underlying submucosa. The epithelial‐lined folds and crypts thus formed are surrounded by aggregations of lymphocytes, which infiltrate this epithelium. Mucous glands are often associated with these lymphoid aggregations. The histological appearance of the laryngeal gland is remarkably similar to the palatine, or dorsal oropharyngeal tonsils, of T. truncatus. It may be analogous to the nasopharyngeal adenoid of terrestrial animals. Age‐related involution of the laryngeal gland is not as obvious with increasing animal age (or length) as it is in other mucosa‐associated lymphoid tissue. The distribution of this gland among cetaceans is not yet known. We have observed it in individuals of every species we have studied, including Lagenodelphis hosei, Stenella coeruleoalba, Stenella attenuata, Globicephala macrorhynchus, Steno bredanensis, Physeter catodon, Pseudorca crassidens, Mesoplodon europaeus, and Kogia breviceps. Anat Rec 254:98–106, 1999. © 1999 Wiley‐Liss, Inc.     

The follicle-sinus complex of the bottlenose dolphin (Tursiops truncatus). Functional anatomy and possible evolutional significance of its somato-sensory innervation

Vibrissae are tactile hairs found mainly on the rostrum of most mammals. The follicle, which is surrounded by a large venous sinus, is called "follicle-sinus complex" (FSC). This complex is highly innervated by somatosensitive fibers and reached by visceromotor fibers that innervate the surrounding vessels. The surrounding striated muscles receive somatomotor fibers from the facial nerve. The bottlenose dolphin (Tursiops truncatus), a frequently described member of the delphinid family, possesses this organ only in the postnatal period. However, information on the function of the vibrissal complex in this latter species is scarce. Recently, psychophysical experiments on the river-living Guiana dolphin (Sotalia guianensis) revealed that the FSC could work as an electroreceptor in murky waters. In the present study, we analyzed the morphology and innervation of the FSC of newborn (n = 8) and adult (n = 3) bottlenose dolphins. We used Masson's trichrome stain and antibodies against neurofilament 200 kDa (NF 200), protein gene product (PGP 9.5), substance P (SP), calcitonin gene-related peptide, and tyrosine hydroxylase (TH) to characterize the FSC of the two age classes. Masson's trichrome staining revealed a structure almost identical to that of terrestrial mammals except for the fact that the FSC was occupied only by a venous sinus and that the vibrissal shaft lied within the follicle. Immunostaining for PGP 9.5 and NF 200 showed somatosensory fibers finishing high along the follicle with Merkel nerve endings and free nerve endings. We also found SP-positive fibers mostly in the surrounding blood vessels and TH both in the vessels and in the mesenchymal sheath. The FSC of the bottlenose dolphin, therefore, possesses a rich somatomotor innervation and a set of peptidergic visceromotor fibers. This anatomical disposition suggests a mechanoreceptor function in the newborns, possibly finalized to search for the opening of the mother's nipples. In the adult, however, this structure could change into a proprioceptive function in which the vibrissal shaft could provide information on the degree of rotation of the head. In the absence of psychophysical experiments in this species, the hypothesis of electroreception cannot be rejected.     

Morphological changes in the Atlantic bottlenose dolphin (Tursiops truncatus) adrenal gland associated with chronic stress

Beach-stranded Atlantic bottlenose dolphins (n=68) were categorized as either "acutely stressed" (if they died from net entanglement, boat strike, or acute infection; 31 animals) or "chronically stressed" (if they suffered from or died as a result of long-term disease or debilitating injury; 37 animals). No significant differences in mass between the right and left adrenal glands were found within each category. However, the average gland mass (AGM), based on the right and left glands together, was 5.2g for acutely stressed animals and 11.01 g for chronically stressed animals (P<0.001). Significant differences were also found, in terms of the ratio of cross-sectional areas of the cortex to medulla, between acutely stressed (ratio 1.22) and chronically stressed (ratio 1.63) animals (P=0.027). Adrenal glands of acutely stressed animals consisted of 48% cortex, 41% medulla, and 11% other tissue elements (connective tissue, blood vessels and gland capsule), whereas the corresponding figures for chronically stressed animals were 53%, 36%, and 11%. The mean estimated mass values for cortex, medulla and other tissue were, for acutely stressed animals, 2.36, 1.9, and 0.54, respectively, whereas for chronically stressed animals the corresponding figures were 6.06, 4.04, and 1.29 (P<0.001 for each of the three comparisons). Overstaining with haematoxylin (HEM) and immunohistochemical labelling (IHC) of the enzyme phenylethanolamine N-methyl transferase (which converts norepinephrine to epinephrine) were used to determine the percentage of epinephrine-producing cells in relation to the overall cross-sectional area of the adrenal gland. The percentage values in acutely as compared with chronically stressed dolphins were 6.7% and 15.93%, respectively (P=0.021). The results therefore suggest that in bottlenose dolphins chronic stress results in increases in (1) adrenal mass, (2) cortex to medulla ratio, and (3) epinephrine-producing cells within the medulla, giving rise to an increase in the thickness of the medullary band.     

Toll-Like Receptors, Inflammation and Tumor in the Human Female Reproductive Tract

Abstract  Toll-like receptors are an important family of pattern recognition receptors. They recognize microbial conserved components and trigger protective responses to the invading pathogens, which constitute a major part of the innate immune system. Toll-like receptors are mainly expressed in immune cells. The current evidences demonstrate that Toll-like receptors are present in some epithelial cells and epithelium derived tumor cells. The expression of Toll-like receptors in these cells is related to infection and inflammation, and tumor progression as well. Genital mucosal epithelium is the first line in defense of microorganism invasion in the female reproductive tract. Toll-like receptors expressed in the genital tract have been implicated in many aspects of reproductive physiology and pathology in the female. In the current review, we will focus on the expression of Toll-like receptors in the female genital mucosa and its association with anti-infection immunity and tumorigenesis.     

Behavioral and anatomical evidence for electroreception in the bottlenose dolphin (Tursiops truncatus)

In the order of cetacean, the ability to detect bioelectric fields has, up to now, only been demonstrated in the Guiana dolphin (Sotalia guianensis) and is suggested to facilitate benthic feeding. As this foraging strategy has also been reported for bottlenose dolphins (Tursiops truncatus), we studied electroreception in this species by combining an anatomical analysis of “vibrissal crypts” as potential electroreceptors from neonate and adult animals with a behavioral experiment. In the latter, four bottlenose dolphins were trained on a go/no-go paradigm with acoustic stimuli and afterward tested for stimulus generalization within and across modalities using acoustic, optical, mechanical, and electric stimuli. While neonates still possess almost complete vibrissal follicles including a hair shaft, hair papilla, and cavernous sinus, adult bottlenose dolphins lack these features. Thus, their “vibrissal crypts” show a similar postnatal morphological transformation from a mechanoreceptor to an electroreceptor as in Sotalia. However, innervation density was high and almost equal in both, neonate as well as adult animals. In the stimulus generalization tests the dolphins transferred the go/no-go response within and across modalities. Although all dolphins responded spontaneously to the first presentation of a weak electric field, only three of them showed perfect transfer in this modality by responding continuously to electric field amplitudes of 1.5 mV cm⁻¹, successively reduced to 0.5 mV cm⁻¹. Electroreception can explain short-range prey detection in crater-feeding bottlenose dolphins. The fact that this is the second odontocete species with experimental evidence for electroreception suggests that it might be widespread in this marine mammal group.     

孕前女性生殖道感染状况分析

目的 了解孕前女性生殖道感染发病情况。方法 对2008年9-12月进行孕前体检的1 254例孕前妇女进行生殖道感染的相关检查,包括阴道炎、急性宫颈炎、盆腔炎、性传播性疾病,并对检查结果进行分析。结果 孕前妇女生殖道感染发病率达23.76%,年龄大、怀孕次数多、丈夫有性伴（≥2人）及有生殖道感染（RTI）自觉症状是危险因素,文化程度高和卫生习惯好则是保护因素。结论 RTI是孕前妇女的常见及多发病,与不良妊娠结局的发生关系密切,应通过宣教提高孕前女性的自我保健能力,改善不良卫生习惯和不洁性行为,从而促进生殖健康。     

Morphology and Ultrastructure of the Amazon River Dolphin (Inia geoffrensis) Spermatozoa

The spermatozoa from seven adult Amazon river dolphins (Inia geoffrensis, CETACEA: INIIDAE) were analyzed by light and electron microscopy. The spermatozoa showed an elongated ellipsoid shaped head and a long tail with a well distinguishable midpiece. The head spermatozoa have a smooth surface like other odontocetes examined, with the exception of the Delphinidae family. The mean dimensions of the spermatozoa were within the range already reported for other cetaceans. The spermatozoa midpiece, as in other cetaceans, showed a random pattern of mitochondria, different from that described for other mammals. Further studies of sperm morphology of a wider spectrum of cetacean families could help to better understand the reproductive biology of these animals and the intergeneric and intrageneric relationships among them, as well as, among other mammals. Anat Rec, 300:1519–1523, 2017. © 2017 Wiley Periodicals, Inc.     

REVIEW ARTICLE: Sex Hormone Regulation of Innate Immunity in the Female Reproductive Tract: The Role of Epithelial Cells in Balancing Reproductive Potential with Protection against Sexually Transmitted Pathogens

Citation Wira CR, Fahey JV, Ghosh M, Patel MV, Hickey DK, Ochiel DO. Sex hormone regulation of innate immunity in the female reproductive tract: the role of epithelial cells in balancing reproductive potential with protection against sexually transmitted pathogens. Am J Reprod Immunol 2010 The immune system in the female reproductive tract (FRT) does not mount an attack against HIV or other sexually transmitted infections (STI) with a single endogenously produced microbicide or with a single arm of the immune system. Instead, the body deploys dozens of innate antimicrobials to the secretions of the female reproductive tract. Working together, these antimicrobials along with mucosal antibodies attack many different viral, bacterial and fungal targets. Within the FRT, the unique challenges of protection against sexually transmitted pathogens coupled with the need to sustain the development of an allogeneic fetus have evolved in such a way that sex hormones precisely regulate immune function to accomplish both tasks. The studies presented in this review demonstrate that estradiol and progesterone secreted during the menstrual cycle act both directly and indirectly on epithelial cells and other immune cells in the reproductive tract to modify immune function in a way that is unique to specific sites throughout the FRT. As presented in this review, studies from our laboratory and others demonstrate that the innate immune response is under hormonal control, varies with the stage of the menstrual cycle, and as such is suppressed at mid‐cycle to optimize conditions for successful fertilization and pregnancy. In doing so, a window of STI vulnerability is created during which potential pathogens including HIV enter the reproductive tract to infect host targets.     

The Role of Sex Hormones and the Tissue Environment in Immune Protection Against HIV in the Female Reproductive Tract

Despite extensive studies of the mucosal immune system in the female reproductive tract (FRT) and its regulation by sex hormones, relatively little attention has been paid to the tissue environment in the FRT that regulates immune cell function. Consisting of secretions from epithelial cells (EC), stromal fibroblasts, and immune cells in tissues from the upper (Fallopian tubes, uterus, and endocervix) and lower (ectocervix and vagina) tracts, each tissue compartment is unique and precisely regulates immune cells to optimize conditions for successful pregnancy and protection against sexually transmitted diseases including HIV. Our goal in this review is to focus on the mucosal (tissue) environment in the upper and lower FRT. Specifically, this review will identify the contributions of EC and fibroblasts to the tissue environment and examine the impact of this environment on HIV‐target cells. Much remains to be learned about the complex interactions with the tissue environment at different sites in the FRT and the ways in which they are regulated by sex hormones and chemical contraceptives. Awareness of the involvement of the tissue environment in determining immune cell function and HIV acquisition is crucial for understanding the mechanisms that lead to HIV prevention, acquisition, and the development of new therapeutic modalities of immune protection.     

A Morphological and 13C NMR Study of the Extramandibular Fat Bodies of the Striped Dolphin (Stenella coeruleoalba)

The molecular and histological structure of the fat bodies covering externally the posterolateral region of the jaw of the striped dolphin (Stenella coeruleoalba) was investigated by means of morphological and nuclear magnetic resonance techniques. The analyses of samples belonging to adult and juvenile individuals were performed with the aim of seeking the presence of age‐related differences. In our study, the level of isovalerate (iso5:0) in the extramandibular fat of the juvenile individuals is comparable with those of the adult counterparts; conversely, longer isobranched fatty acids were detected in lower quantities in the juveniles together with a higher degree of unsaturation. The morphologic analyses revealed that, in both adults and juveniles, this fatty tissue is similar to univacuolar adipose tissue. However, in the juveniles, a muscular component was present, whereas only in adult subjects, enlarged and irregularly shaped cavities may be seen within the adipose tissue. These cavities, structurally organized as veins, may regulate blood flow in response to changing water temperature and stabilize thermal gradient within the jaw lipids. These data suggest that the molecular components and the histological organization can indicate a maturation of the organ with age that probably may reflect different sound reception properties. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.