Role of serotonin, gamma-aminobutyric acid, and glutamate in the behavioral thermoregulation of female tilapia during the prespawning phase.
The role of hypothalamic neurotransmitter systems in behavioral thermoregulation was investigated in the prespawning female tilapia, Oreochromis mossambicus. Intrahypothalamic microinjection with serotonin (5-HT, 3 microliters of 1.0 x 10(-6) M) resulted in a significant increase in the selected temperature. This effect was mimicked by the agonist of 5-HT1A, 1B, and 2C receptors, N-3-trifluoromethylphenyl piperazine. Intrahypothalamic microinjection of tilapia with gamma-aminobutyric acid (GABA) resulted in a biphasic effect of the temperature selection, whereas microinjection with muscimol, an agonist of GABAA receptor, had no effect on temperature selection. Both agonist and antagonist of glutamate (Glu), N-methyl-D-aspartate (NMDA), and MK-801 (1.0 x 10(-6) M), a noncompetitive blocker of NMDA receptor, significantly decreased the preferred temperature. These results indicate that the hypothalamic 5-HT, GABA, and Glu systems play a role in the temperature selection of prespawning female tilapia.
Tsai
Ching-Lin
CL
Department of Marine Resources, National Sun Yat-sen University, Kaohsiung, Taiwan 80424. cltsai@mail.nsysu.edu.tw
Wang
Li-Hsueh
LH
Tsai
Chia-Chiun
CC
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001833:Body Temperature Regulation / Q000187:drug effects*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology*; D007031:Hypothalamus / Q000378:metabolism; D009118:Muscimol / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D012098:Reproduction / Q000187:drug effects*; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology*; D017210:Tilapia / Q000502:physiology*; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000494:pharmacology*
D018690:Excitatory Amino Acid Agonists; D018755:GABA Agonists; D009118:Muscimol; D012701:Serotonin; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate