Suprachiasmatic vasopressin and the circadian regulation of voluntary locomotor behavior

Abstract

A role for arginine vasopressin in the circadian regulation of voluntary locomotor behavior (wheel running activity) was investigated in the golden hamster, Mesocricetus auratus. Spontaneous nocturnal running was suppressed in a dose-dependent manner by systemic injections of vasopressin, and also in a concentration-dependent manner by microinjections directly into the hypothalamic suprachiasmatic nucleus. Pre-injections of a vasopressin V1 receptor antagonist into the nucleus reduced the suppression of behavior by vasopressin. Ethogram analyses revealed that peripheral drug injections predominantly increased grooming, flank marking, and sleep-related behaviors. Central injections did not induce sleep, but increased grooming and periods of 'quiet vigilance' (awake but not moving). Nocturnal behavioral profiles following either peripheral or central injections were similar to those shown by untreated animals in the hour prior to the onset of nocturnal wheel running. Site control vasopressin injections into the medial preoptic area or periaqueductal gray increased flank marking and grooming, but had no significant effect on locomotion, suggesting behavioral specificity of a vasopressin target near the suprachiasmatic nucleus. Both peripheral and central administration increased FOS-like immunoreactivity in the retinorecipient core of the suprachiasmatic nucleus. The distribution of FOS-positive cells overlapped the calbindin subregion, but was more extensive, and most calbindin-positive cells did not co-express FOS. We propose a model of temporal behavioral regulation wherein voluntary behavior, such as nocturnal locomotor activity, is inhibited by the activity of neurons in the suprachiasmatic ventrolateral core that project to the posterior hypothalamus and are driven by rhythmic vasopressin input from the dorsomedial shell.

Nasal Oxytocin Administration Reduces Food Intake without Affecting Locomotor Activity and Glycemia with c-Fos Induction in Limited Brain Areas

“…It is important to note that a high peripheral Oxt concentration can also activate vasopressin receptors that have been reported to regulate locomotor activity [33]. Further studies are required to elucidate the mechanism underlying the effect of IP Oxt administration on locomotor activities.…”

Neonatal exposure to monosodium glutamate induces morphological alterations in suprachiasmatic nucleus of adult rat

“…However, it has been recently shown that locomotor activity is inhibited with systemic injection or microinjection of VP inside SCN (Cormier et al . ). Moreover, it has been reported that there is an association between the increase in locomotor activity and the increase in the number of VP neurons (Bult et al .…”

“…PK2 is present in more than 50% of the cells that contain VP or VIP (Bittman et al, 2009) and CLC is colocalized in VP neurons (Li et al 2009), while TGF-a is expressed in the astrocytes, and therefore, its role continued to be controversial (Li et al 2009). However, it has been recently shown that locomotor activity is inhibited with systemic injection or microinjection of VP inside SCN (Cormier et al 2015). Moreover, it has been reported that there is an association between the increase in locomotor activity and the increase in the number of VP neurons (Bult et al 1993).…”

“…VP and its receptor (VIa) could play an important role in the synchronization of SCN cellular oscillation (Bittman 2009). Moreover, the immunoreactive cells to VP are directly involved in the regulation of the circadian rhythm of locomotor activity as this behaviour is inhibited with systemic injection or microinjection of VP within the SCN (Cormier et al 2015). On the other hand, several studies have shown that astrocytes in SCN play a crucial role in circadian pacemaker function (Prosser et al 1994;Shinohara et al 1995).…”

Musashi‐2 and related stem cell proteins in the mouse suprachiasmatic nucleus and their potential role in circadian rhythms

“…MSI2‘s regulation of the AHR pathway that in turn interacts with the circadian clock is another way it could modify rhythms. MSI2 also controls expression of AVP (Rentas et al, 2016), a major neuropeptide of SCN neurons (Cormier et al, 2015).…”