Central 5-HT3 receptor stimulation by m-CPBG increases blood glucose in rats.
The aim of the present study was to investigate the role of central 5-HT3 receptors on the control of blood glucose in stressed and non-stressed rats in both fasted and fed states. Adult Wistar male rats had each their third ventricle cannulated 7 days before the experiments. Injections of m-CPBG, a selective 5-HT3 receptor agonist, induced a significant increase in blood glucose in non-stressed rats in both fasted and in fed states. The same procedure was unable to modify stress-induced hyperglycemia. The hyperglycemic effect of m-CPBG central administration was blocked by pretreatment with ondansetron, a specific 5-HT3 receptor antagonist, indicating that the effects here obtained with m-CPBG were a result of its interaction with 5-HT3 receptors. Third ventricle injections of ondansetron alone were not able to modify blood glucose in non-stressed animals and did not change the hyperglycemic responses observed after immobilization stress. We conclude that pharmacological activation of the central 5-HT3 receptor induces a hyperglycemic effect in non-stressed animals.
Carvalho
F
F
Department of Physiology, Health Sciences Institute, Federal University of Bahia, Brazil.
Macêdo
D
D
Bandeira
I
I
Maldonado
I
I
Salles
L
L
Azevedo
M F
MF
Rocha
M A
MA
Fregoneze
J B
JB
De Castro-e-Silva
E
E
D000818:Animals; D001645:Biguanides / Q000494:pharmacology*; D001786:Blood Glucose / Q000378:metabolism*; D005215:Fasting; D005502:Food; D007276:Injections, Intraventricular; D007700:Kinetics; D008297:Male; D017294:Ondansetron / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000502:physiology*; D044406:Receptors, Serotonin, 5-HT3; D012149:Restraint, Physical; D012702:Serotonin Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013312:Stress, Physiological / Q000097:blood
D001645:Biguanides; D001786:Blood Glucose; D011985:Receptors, Serotonin; D044406:Receptors, Serotonin, 5-HT3; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D017294:Ondansetron; C065734:1-(3-chlorophenyl)biguanide