Effects of vagotomy on hypoglossal and phrenic responses to hypercapnia in the decerebrate rat

Respiratory rhythm generation and pattern formation: oscillators and network mechanisms

“…The critical deficiency of breathing models predicated exclusively on pacemaker mechanisms to explain the generation of rhythmicity rests upon the necessity for inhibition to terminate the inspiratory epoch, generate expiratory segmentation, and thus resolve triphasic eupnea into inspiratory, postinspiratory, and late expiratory phases . Reciprocal mutual inhibition amongst Bötzinger complex dec post-I (Ezure and Manabe, 1988) and aug late-E ) units underlies expiratory segmentation (Bianchi et al, 1995;Ghali and Marchenko, 2016b;. Specifically, the sequential activity of medullary late inspiratory units (Cohen et al, 1993) and Bötzinger complex glycinergic dec post-I units (Ezure and Manabe, 1988) mediates the inspiratory off switching mechanism (Okazaki et al, 2001;Yamazaki et al, 2000).…”

“…Respiratory central pattern generators (CPGs) operating in different modes and network reconfigurations, thus allow adaptation to respiratory stressors under different conditions. In this regard, the respiratory CPG is subject to powerful modulation by descending inputs from the cerebrum, midbrain, and cerebellum (Horn and Waldrop, 1997) and peripheral inputs from hypercapnia, hypoxia, and lung stretch (Ghali and Marchenko, 2016b;Guyenet et al, 2019). Hypercapnia stimulates central (e.g., RTN, nucleus tractus solitarius [NTS], raphe nuclei) and peripheral chemoreceptors (e.g., glomus cells of the carotid bodies and aortic arch, retroperitoneum) in order to appropriately augment the activity of neurons within the ventral respiratory column nuclei.…”

Microneurosurgical techniques and perioperative strategies utilized to optimize experimental supracollicular decerebration in rats

“…Right phrenic nerve (PNR), hypoglossal nerve (XIIR); PNR and XIIR raw activity (volts); ∫ -integrated PNR and XIIR activity (arbitrary units; au). Modified with permission from Ghali and Marchenko (2016b). median segment of bone overlying the superior sagittal sinus between the ligatures may be performed and the interposed osseous wedge microsurgically drilled using a diamond drill bit connected to a high-speed surgical drill and removed.…”

“…Our use of bilateral internal carotid artery ligation accordingly carries the risk of possible ischemogenic cerebral edema, which may be mitigated by reducing, to the extent permissibly feasible, the interval interposed between vascular ligation and decerebrative transective encephalotomy. Dobson and Marchenko and Sapru (2003), Marchenko and Rogers (2006a), Marchenko and Rogers (2006b), Marchenko and Rogers (2007), Marchenko and Rogers (2009), Marchenko et al (2012), Ghali and Marchenko (2015), Ghali and Marchenko (2015), Ghali and Marchenko (2016a), Ghali and Marchenko (2016b) Pollock and Davis (1930), Bennett et al (1998) Ischemic decerebration via surgical ligation Surgical ligation of internal carotid arteries bilaterally and basilar artery Fouad and Bennett (1998) Ischemic decerebration via embolization Embolization of cranial base arteries Faber et al (1982) Chronic decerebration Supracollicular or midcollicular coronal section without removal of cerebrum excitatory (+, red) and inhibitory (-, blue) synapses. Top: Medullary drive to the phrenic motor nucleus.…”

“…1) (Ghali and Marchenko, 2013;Ghali, 2017c;Marchenko et al, 2012) and demonstrated spontaneous preinspiratory activity in hypoglossal discharge in vagus-intact preparation during hyperoxic normocapnic conditions accentuated and crossmodally modulated by vagotomy and hypercapnia ( Fig. 2) (Ghali and Marchenko, 2016b;Ghali, 2015Ghali, , 2019c, recovery of spontaneous crossed phrenic activity in population neural efferent discharge following high cervical hemisection (Figs. 3 and 4) (Ghali and Marchenko, 2015;Ghali, 2017d), spinal respiratory rhythm generation following high cervical transection (Ghali and Marchenko, 2016a), and recovery of arterial blood pressure to values approximating normal levels following high cervical transection ( Fig.…”