NEUROPEPTIDE-Y STIMULATES FEEDING BUT INHIBITS SEXUAL-BEHAVIOR IN RATS
NEUROPEPTIDE-Y STIMULATES FEEDING BUT INHIBITS SEXUAL-BEHAVIOR IN RATS
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DOI：
10.1210/endo-117-6-2435
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发表时间：
1985-01-01
期刊：
影响因子：
4.8
通讯作者：
KALRA, SP
中科院分区：
文献类型：
--
作者：
CLARK, JT;KALRA, PS;KALRA, SP
研究了神经肽Y（NPY）对雄性和雌性大鼠摄食和性行为的影响，NPY是一种在大鼠脑中发现的富含酪氨酸的肽。在光照期的最后几个小时，脑室内（ivt）注射NPY以剂量相关的方式诱导摄食。虽然最低试验剂量（0.02 nM）没有影响，但较高剂量（0.12、0.47、2.3 nM）在雄性大鼠中均匀引起摄食，潜伏期约为15 min。在最有效剂量0.47 nM下，食物摄入量增加是由于局部进食率增加。相比之下，进食相关肽大鼠胰腺多肽（rPP）后的进食行为模式完全不同，不那么令人印象深刻。在第一个小时内，由于进食时间增加，仅静脉注射一剂rPP（0.45 nM）即可引起食物摄入量增加。此外，NPY对食物摄入的影响在夜间更大。有趣的是，夜间试验（4小时）中食物摄入量的增加仅仅是由于静脉内给药后前60分钟内摄入量的增加。在交配试验中，开始后2小时开始的黑暗和静脉注射肽后10分钟，所有，但最低剂量的NPY（0.01 nM）急剧抑制射精行为。大多数大鼠治疗与较高剂量的NPY（0.02，0.12，或0.47 nM）安装和性活动停止前仅几次，并延长lavelet的初始安装和introdission观察。与NPY诱导的射精行为的显著抑制相反，rPP（0.11和0.45 nM）对交配行为没有影响。为了进一步证实在NYP处理的大鼠中观察到的性行为受损不是由于性能力减弱，进行了额外的实验。静脉注射NYP（0.12 nM）、rPP（0.11 nM）或生理盐水后10分钟，监测阴茎反射，包括勃起。没有观察到NPY或rPP对显示勃起或初始勃起潜伏期的大鼠比例或每次试验的勃起次数的影响。事实上，在NPY后观察到阴茎背屈反应的轻微易化。这些发现表明，NPY选择性地抑制雄性大鼠的性动机。在卵巢切除的雌性大鼠中，对雌激素加孕酮的反应具有良好的性感受性水平（脊柱前凸商数> 70），ivt盐水和0.01 nM NPY对性行为没有影响。然而，在治疗后10分钟开始的测试中，较高剂量的NPY（0.12和0.47 nM）迅速抑制了性行为。观察到接受性显著降低50%，接受行为几乎消失。此外，尽管在盐水（33%安装）和0.01 nM NPY（38%安装）处理组中均观察到低水平的安装（15分钟内1至5次安装），但在用较高NPY剂量处理的动物中未观察到。这些观察结果表明，NPY也可能抑制女性的性行为。这些研究表明，NPY，一种新的下丘脑肽，刺激摄食在雄性大鼠的昼夜和昼夜试验，并抑制雄性和雌性大鼠的性行为。我们认为，神经肽Y可能是一种内源性的神经化学信号，降低性动机，随后增加大鼠的食欲。
The effects of neuropeptide Y (NPY), a tyrosine-rich peptide found in the rat brain, on feeding and sexual behaviour were studied in male and female rats. Intraventricular (ivt) injections of NPY during the final hours of the light period induced feeding in a dose-related manner. While the lowest dose tested (0.02 nm) was without effect, higher doses (0.12, 0.47, 2.3 nM) uniformly elicited feeding with a latency of about 15 min in male rats. With the most effective dose, 0.47 nM, the increased food intake was due to an increased local eating rate. In contrast, the pattern of feeding behavior after a related peptide, rat pancreatic polypeptide (rPP), was quite different and less impressive. During the first hour, only one ivt dose of rPP (0.45 nM) evoked an increase in food intake, due to an increased time spent eating. Further, the effects of NPY on food intake were greater during the nocturnal period. Interestingly increased food intake in nocturnal tests (4 h) was due solely to augmented intake during the first 60 min after ivt administration. In mating tests, initiated 2 h after the onset of darkness and 10 min after ivt administration of peptide, all but the lowest dose of NPY (0.01 nM) drastically suppressed ejaculatory behavior. Most rats treated with higher doses of NPY (0.02, 0.12, or 0.47 nM) mounted and intromitted only a few times before the cessation of sexual activity, and elongated latencies to the initial mount and intromission were observed. In contrast to the dramatic NPY-induced suppression of ejaculatory behavior, rPP (0.11 and 0.45 nM) was without effect on copulatory behavior. To substantiate further that the impairment of sexual behavior seen in NYP-treated rats was not due to an attenuated sexual ability, an additional experiment was performed. Penile reflexes, including erection, were monitored 10 min after ivt injection of NYP (0.12 nM), rPP (0.11 nM), or saline. No effect of NPY or rPP was observed on the proportion of rats showing erection or latency to initial erection, or in the number of erections per test. In fact, a slightly facilitation of penile dorsiflexion responses was seen after NPY. These findings suggest that NPY selectively depresses sexual motivation in the male rat. In ovariectomized female rats responding to estrogen plus progesterone with a good level of sexual receptivity (lordosis quotient > 70), ivt saline and 0.01 nM NPY were without effect on sexual behavior. However, higher doses of NPY (0.12 and 0.47 nM) promptly suppressed sexual behavior in tests initiated 10 min after treatment. A significant 50% decrement in receptivity and a virtual elimination of proceptive behavior were observed. Further, although a low level of mounting (one to five mounts in 15 min) was seen in both the saline (33% mounting) and the 0.01 nM NPY (38% mounting) treated groups, none was observed in animals treated with the higher NPY doses. These observations indicate that NPY may also suppress female sexual behavior. These studies demonstrates that NPY, a novel hypothalamic peptide, stimulates feeding in male rats in both diurnal and nocturanl tests and suppresses sexual behavior in male and female rats. We suggest that NPY may be an endogenous neurochemical signal that decreases sexual motivation and subsequently increases the appetite for food in the rat.