Schechtman V L, Ni H, Glotzbach S F, Harper R M
Brain Research Institute, UCLA School of Medicine, USA.
Sleep. 1997 Jan;20(1):1-10. doi: 10.1093/sleep/20.1.1.
Hypothalamic warming induces panting in cats; in young kittens, panting is interspersed with slower breathing periods. The nature of neural mechanisms underlying these interspersed periods of nonpanting polypnea is unclear. We determined developmental characteristics of nonpanting breathing during thermal stress in kittens and adult cats. Warming electrodes were surgically placed into the preoptic/anterior hypothalamus (POAH) of 19 kittens and six adult cats. After surgical recovery, the hypothalamus was warmed bilaterally during sleep in unrestrained animals. Epochs of nonpanting breathing during periods of POAH warming within quiet sleep (QS) and rapid eye movement sleep (REM) were compared to control periods. Nonpanting polypnea within QS showed inspiratory and expiratory time reductions in the same proportions as those of panting. During REM, increased breathing rates accompanied POAH warming, but inspiratory/expiratory timing characteristics did not differ significantly from those of baseline breathing, except in the youngest kittens. Breathing responses to POAH warming during QS showed significant change as the kittens matured; however, response characteristics during REM did not change significantly from 12 days to adulthood. Responses to thermal stress during QS appear to depend on maturation of neural mechanisms, while separate mechanisms appear to underlie the slight respiratory rate changes during REM.
下丘脑升温会诱发猫喘气；在幼猫中，喘气会夹杂着呼吸较慢的时段。这些夹杂出现的非喘气性呼吸急促时段背后的神经机制本质尚不清楚。我们确定了幼猫和成年猫在热应激期间非喘气呼吸的发育特征。通过手术将加热电极植入19只幼猫和6只成年猫的视前区/下丘脑前部（POAH）。手术恢复后，在未受束缚的动物睡眠期间对双侧下丘脑进行加热。将安静睡眠（QS）和快速眼动睡眠（REM）期间POAH升温时段内的非喘气呼吸时段与对照时段进行比较。QS期间的非喘气性呼吸急促表现为吸气和呼气时间按与喘气相同的比例缩短。在REM期间，POAH升温伴随着呼吸频率增加，但吸气/呼气时间特征与基线呼吸相比无显著差异，最年幼的幼猫除外。随着幼猫成熟，QS期间对POAH升温的呼吸反应出现显著变化；然而，从12天到成年，REM期间的反应特征没有显著变化。QS期间对热应激的反应似乎取决于神经机制的成熟，而REM期间轻微的呼吸频率变化似乎有不同的机制。
