The effect of corazonin on heartbeat reversal in pupae of the tobacco hornworm, Manduca sexta (Lepidoptera: Sphingidae)

Title:

The effect of corazonin on heartbeat reversal in pupae of the tobacco hornworm, Manduca sexta (Lepidoptera: Sphingidae)

Creator:

Sláma, Karel

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:e49f6c12-7842-4c3b-b192-f3d20be36736
uuid:e49f6c12-7842-4c3b-b192-f3d20be36736

Subject:

Heartbeat reversal, anterograde heartbeat, retrograde heartbeat, insect neuropeptides, thermocardiography, optocardiography, [Arg7]-corazonin, proctolin, and CCAP

Type:

article, model:article, and TEXT

Description:

Heartbeat reversal patterns have been monitored in the body of diapausing pupae of M. sexta 2 h before and 3 h after the injections of [Arg7]-corazonin, using noninvasive thermographic and optocardiographic methods. Large dosages (10-6 M final concentrations of corazonin in the body) caused almost immediate, adrenaline-like enhancement of the anterograde heartbeat. During the relatively short, acute phase of the tachycardia induced by corazonin, the systolic anterograde contractions of the heart increased in average from 10.5 to 24 pulses per min, culminating at 2.5 min after the injections. Duration of the acute period of tachycardia was only 7 to 20 min, which was followed by a period of slightly elevated, residual anterograde heartbeat which persisted occasionally for 1 to 3 h. Smaller dosages of corazonin (10-7M concentrations in the body) occasionally also produced a less intensive cardiotropic effect, while the more diluted samples were completely inactive. In pupae of the beetle T. molitor, injections of corazonin (10-6 M in the body) had no effect on the rate of in vivo heartbeat at all. Pharmacological analysis of the effects of corazonin in M. sexta indicated that the cardiostimulating effects of corazonin did not conform with the expected action of a peptidic neurohormone. A possibility that these effects might be artifacts produced by the low molecular breakdown products of corazonin has been discussed.

Language:

English

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Source:

European Journal of Entomology | 2004 Volume:101 | Number:4

Harvested from:

CDK

Metadata only:

false