ORGANIC CATION TRANSPORT BY THE PROXIMAL RENAL TUBULES OF THE GARTER SNAKE, THAMNOPHIS SPP. (TETRAETHYLAMMONIUM).

Persistent Link:
http://hdl.handle.net/10150/186724
Title:
ORGANIC CATION TRANSPORT BY THE PROXIMAL RENAL TUBULES OF THE GARTER SNAKE, THAMNOPHIS SPP. (TETRAETHYLAMMONIUM).
Author:
HAWK, CHARLES TERRANCE.
Issue Date:
1983
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
These studies indicate that tetraethylammonium (TEA) is transported by saturable processes from bath to lumen and lumen to bath in isolated, perfused snake (Thamnophis spp.) proximal renal tubules and that the unidirectional flux from bath to lumen (Jᵇ¹(TEA)) exceeds the unidirectional flux from lumen to bath (J¹ᵇ (TEA)) at all TEA concentrations studied. In order to examine the transport process further, the effects of N¹-methylnicotinamide (NMN), temperature, sodium cyanide, and the removal of Na⁺ on TEA transport were studied. Steady-state Jᵇ¹(TEA) (103.2 ± 1.1 fmoles min⁻¹ mm⁻¹ at {TEA}(b) = 8.1 μM) was inhibited by 50% at {NMN}(b) = 4.0 mM. When TEA and NMN were present in the lumen, J¹ᵇ (TEA) was depressed initially (T < 8 min). However, at steady-state, the presence of NMN in the lumen appeared to stimulate J¹ᵇ (TEA). This suggests a trans-stimulation effect of NMN on J¹ᵇ (TEA). During some flux experiments tubules were perfused at room temperature (24°C) and then cooled to 2.8°C. Jᵇ¹(TEA) decreased approximately 25% when compared to control values. This effect was reversible. Other tubules were perfused in the presence of 2.5 mM sodium cyanide in the perfusate and bath. Cellular concentrations of TEA dropped from 67 to 27 times the bath concentration during Jᵇ¹(TEA) measurements and from 21 to 6 times the mean luminal concentration during J¹ᵇ (TEA) measurements. This indicates that little if any intracellular binding of TEA occurs, as passive accumulation should be 16.1 times the bath or lumen TEA concentration (assuming a -70 mV PD). To determine if TEA transport was dependent on the presence of Na⁺, Na⁺ in the bath and perfusate solutions was replaced isosmotically by sucrose. Jᵇ¹(TEA) was not significantly changed in the absence of Na⁺. J¹ᵇ (TEA) decreased to 56% of control in the absence of Na⁺. This effect was reversible. Thus, J¹ᵇ (TEA) is Na⁺-dependent and Jᵇ¹(TEA) is not. These data suggest that the transport characteristics of the carrier for TEA at the luminal and peritubular membranes of the distal-proximal tubules of garter snakes are dissimilar.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Cations -- Metabolism.; Garter snakes -- Physiology.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Physiology; Graduate College
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleORGANIC CATION TRANSPORT BY THE PROXIMAL RENAL TUBULES OF THE GARTER SNAKE, THAMNOPHIS SPP. (TETRAETHYLAMMONIUM).en_US
dc.creatorHAWK, CHARLES TERRANCE.en_US
dc.contributor.authorHAWK, CHARLES TERRANCE.en_US
dc.date.issued1983en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThese studies indicate that tetraethylammonium (TEA) is transported by saturable processes from bath to lumen and lumen to bath in isolated, perfused snake (Thamnophis spp.) proximal renal tubules and that the unidirectional flux from bath to lumen (Jᵇ¹(TEA)) exceeds the unidirectional flux from lumen to bath (J¹ᵇ (TEA)) at all TEA concentrations studied. In order to examine the transport process further, the effects of N¹-methylnicotinamide (NMN), temperature, sodium cyanide, and the removal of Na⁺ on TEA transport were studied. Steady-state Jᵇ¹(TEA) (103.2 ± 1.1 fmoles min⁻¹ mm⁻¹ at {TEA}(b) = 8.1 μM) was inhibited by 50% at {NMN}(b) = 4.0 mM. When TEA and NMN were present in the lumen, J¹ᵇ (TEA) was depressed initially (T < 8 min). However, at steady-state, the presence of NMN in the lumen appeared to stimulate J¹ᵇ (TEA). This suggests a trans-stimulation effect of NMN on J¹ᵇ (TEA). During some flux experiments tubules were perfused at room temperature (24°C) and then cooled to 2.8°C. Jᵇ¹(TEA) decreased approximately 25% when compared to control values. This effect was reversible. Other tubules were perfused in the presence of 2.5 mM sodium cyanide in the perfusate and bath. Cellular concentrations of TEA dropped from 67 to 27 times the bath concentration during Jᵇ¹(TEA) measurements and from 21 to 6 times the mean luminal concentration during J¹ᵇ (TEA) measurements. This indicates that little if any intracellular binding of TEA occurs, as passive accumulation should be 16.1 times the bath or lumen TEA concentration (assuming a -70 mV PD). To determine if TEA transport was dependent on the presence of Na⁺, Na⁺ in the bath and perfusate solutions was replaced isosmotically by sucrose. Jᵇ¹(TEA) was not significantly changed in the absence of Na⁺. J¹ᵇ (TEA) decreased to 56% of control in the absence of Na⁺. This effect was reversible. Thus, J¹ᵇ (TEA) is Na⁺-dependent and Jᵇ¹(TEA) is not. These data suggest that the transport characteristics of the carrier for TEA at the luminal and peritubular membranes of the distal-proximal tubules of garter snakes are dissimilar.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectCations -- Metabolism.en_US
dc.subjectGarter snakes -- Physiology.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePhysiologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.identifier.proquest8322642en_US
dc.identifier.oclc690021206en_US
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