Participação das vias alfa 2 - adrenérgica, dopaminérgica e gabaérgica no controle da secreção de GH no período pré-púbere de novilhas da raça nelore
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Data
2011-02-07
Autores
Batista, Emiliana de Oliveira Santana [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Foi avaliada a variação na concentração de GH em resposta a agonistas ou antagonistas de neurotransmissores durante o período pré-púbere em 10 novilhas da raça Nelore. A administração de um antagonista gabaérgico (picrotoxina, 0,18 mg/kg, I.V., amostras a cada 15 min por 10 h) aumentou a concentração de GH aos 10 meses de idade, mas não aos 14 e 17 meses. Tanto no grupo Picrotoxina, como no Controle a concentração média de GH foi maior aos 10 meses do que aos 17 meses de idade. O grupo picrotoxina apresentou aos 17 meses maior área de concentração de GH que o controle. O grupo picrotoxina apresentou aos 14 meses maior área total de picos que o controle. Aos 10 e 14 meses no grupo Picrotoxina houve maior amplitude de picos do que aos 17 meses. Bloqueando o receptor (D2) dopaminérgico (sulpiride, 0,59 mg/kg, SC, amostras a cada 15 min por 10 h) houve aumentou na concentração de GH aos 8 e 12 meses, mas não aos 16 meses de idade, comparado ao grupo controle. No grupo Sulpiride a concentração média de GH foi maior aos 8 e 12, comparado com os 16 meses de idade. Em relação à área total de secreção, área total de picos, e amplitude máxima de picos de secreção de GH não houve diferença entre os grupos. Aos 8 meses o grupo Sulpiride apresentou menor tempo, porém aos 12 meses o tempo foi maior para o primeiro pico em relação ao controle. O tempo para o primeiro pico foi menor aos 8 e 16 meses que aos 12 meses no grupo Sulpiride. No grupo controle aos 12 meses o tempo para o primeiro pico foi menor que aos 8 e 16 meses. Aos 16 meses o grupo Sulpiride apresentou maior freqüência de picos que o Controle. A aplicação de um estimulador alfa-adrenérgico (clonidina, 10 µg/kg, I.V., amostras a cada 15 min por 4 h) aumentou a concentração média de GH aos 8 e 15 meses em relação ao grupo Controle e em alguns intervalos aos 12 meses...
This study evaluated the GH concentration after neurotransmitter agonist or antagonists injection in prepubertal Nelore heifers at different ages. A gabaergic antagonist (picrotoxin, 0.18 mg/kg,I.V., samples every 15 min for 10h) promoted an increase on GH concentration at 10 months of age but not at 14 and 17 mo. In both Picrotoxin and Control groups GH average concentration was higher at 10 mo than at 17 month of age. At 17 mo the picrotoxin group had a larger GH concentration area than control. There was no difference among the groups on the time for the first GH surge, but at 14 mo the Picrotoxin group had a higher total peak area than control. At 10 and 14 mo the Picrotoxin group had an higher peak amplitude than at 17 months. Blocking the D2-dopaminergic receptor (Sulpiride 0.59 mg/kg, SC, samples every 15 min for 10 h) there was an increase on GH secretion at 8 and 12 months, but not at 16 mo of age, compared to control group. Inside Sulpiride group the average GH concentration was higher at 8 and 12 mo than at 16 month of age. For both total area, peaks total area, time for first peak, and peak maximal amplitude there was no difference among groups. The time for the first GH peak was lower for Sulpiride compared to Control group at 8 mo, but at 12 mo the time was higher than in Control. Inside Sulpiride group time was lower at 8 and 16 month compared to 12. In the control group time for the first peak was lower at 12 than 8 and 16 months. At 16 month the Sulpiride group had higher peak frequency than Control. An alpha adrenergic stimulation (Clonidine, 10 µg/kg, IV, samples every 15 min for 4 h) increased mean GH concentration at 8 and 15 months compared to Control group and at some intervals at 12 months. At 8 months Clonidine group had higher total secretion area, total peak area, maximum peak amplitude and lowe time for the first GH secretion peak, compared... (Complete abstract click electronic access below)
This study evaluated the GH concentration after neurotransmitter agonist or antagonists injection in prepubertal Nelore heifers at different ages. A gabaergic antagonist (picrotoxin, 0.18 mg/kg,I.V., samples every 15 min for 10h) promoted an increase on GH concentration at 10 months of age but not at 14 and 17 mo. In both Picrotoxin and Control groups GH average concentration was higher at 10 mo than at 17 month of age. At 17 mo the picrotoxin group had a larger GH concentration area than control. There was no difference among the groups on the time for the first GH surge, but at 14 mo the Picrotoxin group had a higher total peak area than control. At 10 and 14 mo the Picrotoxin group had an higher peak amplitude than at 17 months. Blocking the D2-dopaminergic receptor (Sulpiride 0.59 mg/kg, SC, samples every 15 min for 10 h) there was an increase on GH secretion at 8 and 12 months, but not at 16 mo of age, compared to control group. Inside Sulpiride group the average GH concentration was higher at 8 and 12 mo than at 16 month of age. For both total area, peaks total area, time for first peak, and peak maximal amplitude there was no difference among groups. The time for the first GH peak was lower for Sulpiride compared to Control group at 8 mo, but at 12 mo the time was higher than in Control. Inside Sulpiride group time was lower at 8 and 16 month compared to 12. In the control group time for the first peak was lower at 12 than 8 and 16 months. At 16 month the Sulpiride group had higher peak frequency than Control. An alpha adrenergic stimulation (Clonidine, 10 µg/kg, IV, samples every 15 min for 4 h) increased mean GH concentration at 8 and 15 months compared to Control group and at some intervals at 12 months. At 8 months Clonidine group had higher total secretion area, total peak area, maximum peak amplitude and lowe time for the first GH secretion peak, compared... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Somatotropina, Zebu, Picrotoxina, Sulpiride, Clonidina, Maturidade sexual, Prepubertal, Growth hormone, Bos Indicus, Picrotoxin, Sulpiride, Clonidine
Como citar
BATISTA, Emiliana de Oliveira Santana. Participação das vias alfa 2 - adrenérgica, dopaminérgica e gabaérgica no controle da secreção de GH no período pré-púbere de novilhas da raça nelore. 2011. 106 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade Odontologia e Curso Medicina Veterinária, 2011.