The hypothalamus plays an important role in the regulation of several visceral processes, including food intake, thermoregulation and control of anterior pituitary secretion. Endogenous cannabinoids and CB(1) cannabinoid receptors have been found in the hypothalamus. In the present review, we would like to clarify the role of the endocannabinoid system in the regulation of the above-mentioned visceral functions. There is historical support for the role of marihuana (i.e. exogenous cannabinoids) in the regulation of appetite. Endocannabinoids also stimulate food intake. Furthermore, the specific CB(1) receptor antagonist SR141716 reduces food intake. Leptin treatment decreases endocannabinoid levels in normal rats and ob/ob mice. These findings provide evidence for the role of the hypothalamic endocannabinoid system in food intake and appetite regulation. Cannabinoids can change body temperature in a dose-dependent manner. High doses cause hypothermia while low doses cause hyperthermia. Cannabinoid administration decreases heat production. It seems that the effects of can- nabinoids on thermoregulation is exerted by altering some neurochemical mediator effects at both the presynaptic and postsynaptic level.THC and endocannabinoids have mainly inhibitory effects on the regulation of reproduction. Administration of anandamide (AEA) decreases serum luteinizing hormone (LH) and prolactin (PRL) levels. AEA causes a prolongation of pregnancy in rats and temporarily inhibits the postnatal development of the hypothalamo-pituitary axis in offspring. The action of AEA on the reproductory parameters occurs at both the hypothalamic and pituitary level. CB(1) receptors have also been found in the anterior pituitary. Further, LH levels in CB(1) receptor-inactivated mice were decreased compared with wild-type mice. Taken together, all these observations suggest that the endocannabinoid system is playing an important part in the regulation of the mentioned visceral functions and it provides the bases for further applications of cannabinoid receptor agonists and/or antagonists in visceral diseases regulated by the hypothalamus.

Animals↗

PubMedDate not supplied

Presence of neuropeptide--Y and its C-terminal flanking peptide immuno-reactivity in the seminiferous tubules of human testis.

The presence of neuropeptide Y (NPY) and its C-terminal flanking peptide (C-PON) was described by immunohistochemistry in human testes. The immunopositive material was visualized in the spermatogenic elements of the seminiferous tubules. More NPY occurred in the younger testis and more C-PON in the older ones. NPY positive material was present mainly in the spermatogonia, and in the primary spermatocytes, where C-PON also occurred. The megalospermatocytes, present in aged testis, showed C-PON immunoreactivity. Both NPY and C-PON were present in granular form in the perinuclear zone of the cells. No positive material was detected in the Sertoli cells or in the Leydig cells. It is possible that NPY and its precursor are synthetized within the testis and might play a role in the paracrine and/or autocrine regulation of spermatogenesis.

Adult↗