Activity In Lateral Hypothalamic Area Research Articles

Lateral hypothalamic activity indicates hunger and satiety states in humans.

Lateral hypothalamic area (LHA) local field potentials (LFPs) were recorded in a Prader–Willi patient undergoing deep brain stimulation (DBS) for obesity. During hunger, exposure to food‐related cues induced an increase in beta/low‐gamma activity. In contrast, recordings during satiety were marked by prominent alpha rhythms. Based on these findings, we have delivered alpha‐frequency DBS prior to and during food intake. Despite reporting an early sensation of fullness, the patient continued to crave food. This suggests that the pattern of activity in LHA may indicate hunger/satiety states in humans but attest to the complexity of conducting neuromodulation studies in obesity.

Effect of anorexinergic peptides, cholecystokinin (CCK) and cocaine and amphetamine regulated transcript (CART) peptide, on the activity of neurons in hypothalamic structures of C57Bl/6 mice involved in the food intake regulation

The hypothalamus plays an important role in food consumption, receiving information about energy balance via hormonal, metabolic, and neural inputs. Its neurons produce neuropeptides influencing energy balance. Especially important to regulation of food consumption are certain hypothalamic structures, including the arcuate (ARC) and ventromedial (VMN) nuclei and the lateral hypothalamic area (LHA). We determined the impact of cholecystokinin (CCK) and cocaine and amphetamine regulated transcript (CART) peptide, on activity of ARC and VMN neurons and hypocretin (Hcrt) synthesizing neurons in LHA. ARC is an integrative nucleus regulating food consumption, VMN is considered to be a satiety centre, and LHA a hunger sensing centre. After overnight fasting, male C57Bl/6 mice received intraperitoneal injection of (i.p.) saline (SAL) or CCK (4μg/kg) or intracerebroventricular injection of (i.c.v.) CART peptide (0.1μg/mice) or CCK (i.p.) followed by CART peptide (i.c.v.) 5min later. Sixty minutes later, the presence of Fos or Fos/Hcrt immunostaining indicated activity of ARC and VMN neurons, as well as of Hcrt cells in LHA. CCK alone did not influence neuronal activity in any of the nuclei studied. CART peptide stimulated neurons in ARC and VMN (p<0.01) but decreased Hcrt neuronal activity in LHA (p<0.05). Co-administration of both peptides synergistically stimulated ARC neurons (p<0.01) and asynergistically inhibited LHA Hcrt neurons (p<0.01). Results indicate that CCK may modify the effect of CART peptide and thus substantially influence activity of neurons in hypothalamic structures involved in regulation of food intake.

Influences of cerebellar interpositus nucleus and fastigial nucleus on neuronal activity of lateral hypothalamic area

Stimulation of cerebellar interpositus nucleus and fastigial nucleus could influence the neuronal activity of lateral hypothalamic area in the cat, and some of the neurons which respond to the cerebellar stimulations are glucose-sensitive neurons. These results suggest that the cerebellum is involved not only in motor control, but also in the regulation of non-somatic functions through the cerebello-hypothalamic pathways.

Cerebellar interpositus nucleus modulates neuronal activity of lateral hypothalamic area.

Effects of stimulating the cerebellar interpositus nucleus (IN) on the neuronal activity of lateral hypothalamic area (LHA) were first observed in the cat. The results showed that (1) IN stimulation could elicit inhibitory, excitatory, inhibitory-excitatory and excitatory-inhibitory responses from LHA neurones, with a majority of inhibitory responses (46.9%); (2) the responsive latencies of LHA neurones to IN stimulation ranged from 5 to 45 ms, while most (83.6%) showed a short latency of < 15 ms; (3) of 67 LHA neurones which responded to the IN stimulation, 42 (62.7%) cells were identified to be glucose-sensitive neurones. These results suggest that IN may be involved in the role of LHA modulating food intake behaviour, as well as other non-somatic functions.

Calcitonin-induced anorexia in rats: Evidence for its inhibitory action on lateral hypothalamic chemosensitive neurons

Effects of a synthetic derivative of eel calcitonin, [Asu 1,7]ECT on feeding behavior, and its direct action on the neuronal activity of lateral hypothalamic area (LHA) were studied in rats. Food intake was significantly reduced in a dose-dependent manner after intra-third ventricular injection of [Asu 1,7]ECT (0.2–1.0 U/rat). The neuronal activity of LHA neurons, especially the glucose-sensitive neurons, was inhibited by electrophoretic application of [Asu 1,7]ECT. The inhibition was accompanied by a hyperpolarization of the membrane by about 5–7 mV with an increase in the membrane resistance (5.0–8.7%). This effect was also shown to be independent of noradrenergic or serotonergic mechanisms. Phosphodiesterase inhibitors, such as 3-isobutyl-1-methylxanthine and papaverine augmented the inhibitory response, whereas nicotinic acid blocked it. These results suggest that the anorexia caused by [Asu 1,7]ECT is mediated through a direct inhibition of chemosensitive neuronal activity in the LHA, caused by an increase in the intracellular level of cyclic 3′, 5′-adenosine monophosphate.

Activity of neurons of the hypothalamic suprachiasmatic nuclei and circadian rhythms: the role of the suprachiasmatic nuclei in rhythmic activities of neurons in the lateral hypothalamic area and ventromedian nuclei and the control of the pineal gland

Unit activity of lateral hypothalamic area (LHA) and ventromedian nuclei (VMN) was recorded in urethane anesthetized male rats. A 5 to 10 sec, a 3 to 5 min and a circadian rhythmicity were observed. In about 15% of all neurons, spontaneous activity of LHA and VMN showed reciprocal relationships. Subthreshold stimuli applied at a slow rate in the septum and the suprachiasmatic nuclei (SCN) suppressed the rhythms without changing firing rates. On the other hand stimulation of the optic nerve at a rate of 5 to 10/sec increased firing rates in one third of neurons of SCN. Iontophoretically applied acetycholine increased 80% of tested neurons of SCN, whereas norepinephrine, dopamine and 5HT inhibited 64%, 60% and 75% of SCN neurons, respectively. These inhibitions were much stronger in neurons, the activity of which was increased by optic nerve stimulation. Stimulation of the SCN inhibited the tonic activity in cervical sympathetic nerves. These data suggest that SCN plays a significant role in controlling the rhythmic activity of LHA, VMN and the pineal gland. Dopamine and 5HT may be involved in regulation of the firings of SCN neurons.