Neurotensin and cholecystokinin depress motility in isolated Lumbricus terrestris crop-gizzard preparations

Document Type

Article

Abstract

The effects of neurotensin (NT) and cholecystokinin (CCK) were studied on isolated crop-gizzard preparations of Lumbricus terrestris suspended in a smooth muscle organ bath. Changes in the amplitude and frequency of contractions associated with spontaneous motility were observed in response to neurotransmitters known to have an excitatory effect (acetylcholine) and an inhibitory effect (serotonin); and to the hormones NT and CCK, which in vertebrate models have both been shown to inhibit gastric motility. The overall contractile amplitude and frequency of crop-gizzard contractions were decreased in response to increasing concentrations of NT and CCK. In general, both hormone-induced responses were similar when compared at equal molar concentrations. Cholecystokinin, however, did exhibit a greater reduction in contractile frequency than NT. It is speculated that possible desensitization of earthworm NT-receptors to higher hormone concentrations resulted in a depressed maximal response in the concentration-response curve. Despite that possibility, the overall hormonal inhibition was statistically significant. These results infer that NT- and CCK-induced inhibition of crop-gizzard motility may have a modulatory role in the transport of nutrients and overall efficiency of worm metabolism. © 2008 Elsevier Inc. All rights reserved.

Department(s)

Biological Sciences

Publication Title

Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology

Volume

151

Issue

4

First Page

682

Last Page

686

Publication Date

1-1-2008

DOI

10.1016/j.cbpa.2008.08.022

ISSN

10956433

E-ISSN

15314332

PubMed ID

18790067

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