Morphology and histochemistry of the mast cells of snakes

Sottovia-Filho, D.

doi:10.1002/jmor.1051420106

Cited by 15 publications

(14 citation statements)

References 27 publications

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“…The high concentration of antiinflammatory cells (plasma-like cells and mast cells) in the lamina propria of the nonglandular uterus undoubtedly helps to aid against this occurrence. Mast cells have been recorded in the oviducts of other snakes (Sottovia-Filho, 1973, 1974Blackburn, 1998); however, this is the first investigation that has observed plasma-like cell invasion in the intercellular canaliculi of the epithelium in the oviduct.…”

Section: The Nonglandular Uterusmentioning

confidence: 90%

Sperm aggregations in female Agkistrodon piscivorus (Reptilia:Squamata): A histological and ultrastructural investigation

Siegel

Sever

2007

Journal of Morphology

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Upon copulation in female Agkistrodon piscivorus, sperm migrate up the oviduct to sperm storage tubules (SSTs) in the posterior infundibulum. The epithelium of the SSTs is composed of ciliated and secretory cells and differs ultrastructurally from that of the epithelium lining the lumen of the posterior infundibulum. Sperm pass through an area composed primarily of ciliated cells at the opening of each gland before aligning themselves in parallel arrays with their nuclei facing an area composed primarily of secretory cells at the base of the tubules. Sperm are also found embedded inter- and intracellularly in the SSTs. The secretory vacuoles in the SSTs become highly electron dense after the start of the fall mating season along with the synthesis of lipid droplets. Histochemical analysis reveals that the alteration in secretory material density is caused by the production of neutral carbohydrates. Some sperm remain in aggregates in the nonglandular section of the posterior uterus until the time of ovulation. However, ultrastructural evidence indicates these sperm degrade before ovulation. Therefore, sperm in posterior aggregates have no role in fertilization of ovulated ova. The data presented here support the hypothesis that infundibular sperm storage is the mode that snakes utilize to sequester viable sperm until ovulation.

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Section: The Nonglandular Uterusmentioning

confidence: 90%

Sperm aggregations in female Agkistrodon piscivorus (Reptilia:Squamata): A histological and ultrastructural investigation

Siegel

Sever

2007

Journal of Morphology

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“…In mammals, NT causes histamine release from mast cells (7,16,17,18), and several of the effects produced by NT, including increased vascular permeability and hypotension, are mimicked by histamine and can be blocked by histamine antagonists, mast cell depletion, or mast cell stabilization (8,24). Mast cells have been identified in snakes (37), and histamine dilates the systemic vasculature of the python P. regius that can be blocked by the H 2 -receptor antagonist, ranitidine (N. Skovgaard and T. Wang, unpublished observation). However, the systemic vasodilation produced by NT in pythons could not be blocked by H 2 receptor blockade, indicating that the vascular effects of NT are unlikely to be mediated through the release of histamine.…”

Section: Hemodynamic Effects Of Neurotensin Before and After ␤-Adrementioning

confidence: 99%

Evidence that neurotensin mediates postprandial intestinal hyperemia in the python,Python regius

Skovgaard¹,

Conlon²,

Wang³

2007

American Journal of Physiology-Regulatory, Integrative and Comp

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Digestion of large meals in pythons produces substantial increases in heart rate and cardiac output, as well as a dilation of the mesenteric vascular bed leading to intestinal hyperemia, but the mediators of these effects are unknown. Bolus intra-arterial injections of python neurotensin ([His(3), Val(4), Ala(7)]NT) (1 - 1,000 pmol/kg) into the anesthetized ball python Python regius (n = 7) produced a dose-dependent vasodilation that was associated with a decrease in systemic pressure (P(sys)) and increase in systemic blood flow (Q(sys)). There was no effect on pulmonary pressure and conductance. A significant (P < 0.05) increase in heart rate (f(H)) and total cardiac output (Q(tot)) was seen only at high doses (>30 pmol/kg). The systemic vasodilation and increase in Q(tot) persisted after beta-adrenergic blockade with propranolol, but the rise in f(H) was abolished. Also, the systemic vasodilation persisted after histamine H(2)-receptor blockade. In unanesthetized pythons (n = 4), bolus injection of python NT in a dose as low as 1 pmol/kg produced a significant increase in blood flow to the mesenteric artery (177% +/- 54%; mean +/- SE) and mesenteric conductance (219% +/- 74%) without any increase in Q(sys), systemic conductance, P(sys), and f(H). The data provide evidence that NT is an important hormonal mediator of postprandial intestinal hyperemia in the python, but its involvement in mediating the cardiac responses to digestion may be relatively minor.

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“…A major store of histamine in vertebrates is mast cells that are distributed throughout the body, including cardiac tissue (39,49). In digesting mammals, gastrin is released from the pyloric antrum of the stomach from specialized cells, released into the bloodstream, and carried to the enterochromaffin-like cells in the gastric mucosa, where it stimulates the release of histamine through cholecystokinin 2 receptors (25).…”

Section: Role Of Histamine During Digestion In Pythonsmentioning

confidence: 99%

Histamine induces postprandial tachycardia through a direct effect on cardiac H₂-receptors in pythons

Skovgaard¹,

Møller²,

Gesser³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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The intrinsic heart rate of most vertebrates studied, including humans, is elevated during digestion, suggesting that a nonadrenergic-noncholinergic factor contributes to the postprandial tachycardia. The regulating factor, however, remains elusive and difficult to identify. Pythons can ingest very large meals, and digestion is associated with a marked rise in metabolism that is sustained for several days. The metabolic rise causes more than a doubling of heart rate and a fourfold rise in cardiac output. This makes the python an interesting model to investigate the postprandial tachycardia. We measured blood pressure and heart rate in fasting Python regius, and at 24 and 48 h after ingestion of a meal amounting to 25% of body wt. Digestion caused heart rate to increase from 25 to 56 min, whereas blood pressure was unchanged. The postprandial rise in heart rate was partially due to a doubling of intrinsic heart rate. The H(2)-antagonist did not affect heart rate of fasting snakes but decreased heart rate by 15-20 min at 24 h into digestion, whereas it had no effects at 48 h. Thus, the histaminergic tone on the heart rose from none to 30% at 24 h but vanished after 48 h. In anesthetized snakes, histamine caused a systemic vasodilatation and a marked increase in heart rate and cardiac output mediated through a direct effect on H(2)- receptors. Our study strongly indicates that histamine regulates heart rate during the initial phase of digestion in pythons. This study describes a novel regulation of the vertebrate heart.

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Morphology and histochemistry of the mast cells of snakes

Cited by 15 publications

References 27 publications

Sperm aggregations in female Agkistrodon piscivorus (Reptilia:Squamata): A histological and ultrastructural investigation

Sperm aggregations in female Agkistrodon piscivorus (Reptilia:Squamata): A histological and ultrastructural investigation

Evidence that neurotensin mediates postprandial intestinal hyperemia in the python,Python regius

Histamine induces postprandial tachycardia through a direct effect on cardiac H₂-receptors in pythons

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Morphology and histochemistry of the mast cells of snakes

Cited by 15 publications

References 27 publications

Sperm aggregations in female Agkistrodon piscivorus (Reptilia:Squamata): A histological and ultrastructural investigation

Sperm aggregations in female Agkistrodon piscivorus (Reptilia:Squamata): A histological and ultrastructural investigation

Evidence that neurotensin mediates postprandial intestinal hyperemia in the python,Python regius

Histamine induces postprandial tachycardia through a direct effect on cardiac H2-receptors in pythons

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Histamine induces postprandial tachycardia through a direct effect on cardiac H₂-receptors in pythons