ANSWER ALL THREE QUESTIONS ATTAHED:

Answer all three questions attahed:

Answer all three questions

Experiment 1

The effect on the middle cerebral artery blood flow velocity (VMCA) of moderate and hard physical exercise on an ergometer cycle was examined in 10 healthy volunteers using transcranial Doppler sonography (TCD) (Altman 2005). During exercise, the heart rate increased by 136% and the systolic blood pressure by 37% (mean values) (Altman 2005). During initial moderate exercise, VMCA increased by 51%; in a following period of maximal physical work, VMCA decreased again by 20% in 9 of 10 volunteers although the heart rate continued to increase by 10% and the systolic blood pressure by 5% (mean values).

Constriction of the MCA may explain the initial increase of VMCA, suggesting a role for large cerebral arteries in autoregulation. Our data indicate that the subsequent decrease of VMCA is caused by arteriolar constriction, a likely cause of which was hyperventilation during the excessive work period (Abrous 2005).

Recent findings have linked exercising regularly with increased cerebral blood flow and a greater number of blood vessels in the brain.

Experiment 2

Recently, physical exercise has been shown to significantly alter neurochemistry and neuronal function and to increase neurogenesis in discrete brain regions. Although we have documented that physical exercise leads to molecular changes in the posterior hypothalamic area (PHA), the impact on neuronal activity is unknown (Abrous 2005). The purpose of the present study was to determine whether neuronal activity in the PHA is altered by physical exercise. Spontaneously hypertensive rats (SHR) were allowed free access to running wheels for a period of 10 wk (exercised group) or no wheel access at all (nonexercised group). Single-unit extracellular recordings were made in anesthetized in vivo whole animal preparations or in vitro brain slice preparations. The spontaneous firing rates of PHA neurons in exercised SHR in vivo ...