Gill circulation: regulation of perfusion distribution and metabolism of regulatory molecules.

摘要: The fish gill is the primary regulatory interface between internal and external milieu a variety of neurocrine, endocrine, paracrine, autocrine signals coordinate control functions. Many these messengers also affect vascular resistance, they, in turn, may be inactivated (or activated) by branchial vessels. Few studies have critically addressed how flow distributed within filament, physiological consequences thereof, or impact hormone metabolism on systemic homeostasis. In most fish, entire cardiac output perfuses arterioarterial pathway, this network probably accounts for majority passive- stimulus-induced changes resistance. in-series arrangement extensive microcirculation with vessels indicative high capacity plasma-borne as well xenobiotics. Adenosine, arginine vasotocin (AVT), endothelin (ET) are potent constrictors identified to date, all decrease lamellar perfusion. Perhaps not surprising, they Acetylcholine favors perfusion alamellar filamental vasculature, although relevance acetylcholine-mediated responses remains unclear. Angiotensin, bradykinin, urotensin, natriuretic peptides, prostaglandins, nitric oxide vasoactive varying degrees, but their effects intrafilamental blood unknown. If form befits function, then complex anatomy suggests level sophistication unparalleled other vertebrate organs. Resolution issues will technically challenging unquestionably rewarding.