Role of testosterone on pain threshold in rats.

Pain thresholds were recorded in rats by progressive increase in electrical stimulation to induce tail withdrawal, vocalisation and vocalisation after discharge. It was observed that castration resulted in significant reduction of pain threshold which however returned to normal level on substitution with testosterone therapy.

Effect of duration of stress on pain threshold in rats.

Rats were subjected to immobilization stress of varying duration and their pain thresholds were recorded. It was seen that stress of lesser duration did not affect the endogenous opioid analgesic system while stressor of longer duration stimulated this system to its maximum irrespective of further increasing the duration of the stress condition even upto two fold.

Role of striatal dopamine in the lordosis behaviour.

Effects of intrastriatal injections of haloperidol (Dopamine antagonist) and D-amphetamine (Dopamine agonist) on lordosis behaviour were studied in ovariectomized female albino rats, after priming with subcutaneous injections of estrogen and progesterone. The lordosis quotient (LQ) significantly increased after haloperidol, and decreased following D-amphetamine treatment. However, the inhibitory effect of D-amphetamine was transient and could be reversed by haloperidol in the same animal when given one hour after the D-amphetamine injection.

Effect of intensity and duration of stress on male sexual behaviour.

Male rats were exposed to four different stress conditions, varying in duration and intensity, during separate periods and their copulatory behaviour was studied. The number of mounts and time spent in other sexual behaviours were reduced with intensity of stressor being primarily responsible rather than prolongation of duration of a less severe stress condition.

Role of caudate nucleus on modulation of blood pressure responses in cat.

Changes in blood pressure, heart rate and respiration were studied in 15 cats on bilateral stimulation of rostral, middle and caudal regions of caudate nucleus. Hypotensive response was obtained on stimulation of anterior caudate nucleus, which changed to pressor response when posterior caudate nucleus was stimulated. Biphasic blood pressure responses were recorded on stimulation of middle caudatal area.