Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 Aug;180(6):825-34.
doi: 10.1007/s00360-010-0464-z. Epub 2010 Mar 18.

Hormone-dependent Dissociation of Blood Flow and Secretion Rate in the Lingual Salt Glands of the Estuarine Crocodile, Crocodylus Porosus

Affiliations

Hormone-dependent Dissociation of Blood Flow and Secretion Rate in the Lingual Salt Glands of the Estuarine Crocodile, Crocodylus Porosus

Rebecca L Cramp et al. J Comp Physiol B. .

Abstract

Salt and water balance in the estuarine crocodile, Crocodylus porosus, involves the coordinated action of both renal and extra-renal tissues. The highly vascularised, lingual salt glands of C. porosus excrete a concentrated sodium chloride solution. In the present study, we examined the in vivo actions of vasoactive intestinal peptide (VIP), B-type natriuretic peptide (BNP) and angiotensin II (ANG II) on the secretion rate and blood perfusion of the lingual salt glands. These peptides were selected for their vasoactive properties in addition to their reported actions on salt gland activity in birds and turtles and rectal gland activity in elasmobranchs. The femoral artery was cannulated in seven juvenile crocodiles for delivery of peptides and measurement of mean blood pressure and heart rate. In addition, secretion rate of, and blood flow to, the salt glands were recorded simultaneously using laser Doppler flowmetry. VIP stimulated salt secretion was coupled to an increase in blood flow and vascular conductance of the lingual salt glands. BNP was a potent stimulant of salt gland secretion, resulting in a maximal secretion rate of more than 15-fold higher than baseline; however, this was not coupled to an increase in perfusion rate, which remained unchanged. ANG II failed to stimulate salt gland secretion and there was a transient decrease in salt gland blood flow and vascular conductance. It is evident from this study that blood flow to, and secretion rate from, the lingual salt glands of C. porosus are regulated independently; indeed, it is apparent that maximal secretion from the salt glands may not require maximal blood flow.

Similar articles

See all similar articles

References

    1. Am J Physiol. 1997 Sep;273(3 Pt 2):R1080-5 - PubMed
    1. J Exp Zool. 1990 Jun;254(3):237-47 - PubMed
    1. Braz J Med Biol Res. 1995 Nov-Dec;28(11-12):1207-16 - PubMed
    1. J Exp Biol. 1983 Sep;106:25-41 - PubMed
    1. J Comp Physiol B. 1998 Apr;168(3):213-24 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources

Feedback